Introduction

Public Service Motivation refers to the intrinsic drive that motivates individuals to voluntarily engage in public service1. At its core, PSM is centered on serving the public and promoting public interests. It is inherently altruistic, reflecting an individual’s commitment to public affairs, as well as their dedication, service, and willingness to make sacrifices for the common good2. From a psychological perspective, Public Service Motivation (PSM) can be understood as an internal driving force—a power that inspires, guides, and sustains individuals’ engagement in public service. In China, more than 10 million college students graduate each year, many of whom are regarded as the future pillars of society, with an increasing number actively participating in various public service activities3. The motivations of college students for public service play a crucial role in advancing a country’s public utilities. Therefore, it is vital for both the government and academia to focus on understanding and enhancing these motivations. This includes identifying the key factors that influence them, exploring the internal mechanisms that drive students to engage in public service, and implementing strategies to foster and strengthen their Public Service Motivation. By doing so, not only will individuals benefit, but society as a whole will also thrive. This highlights the importance of clarifying the Public Service Motivations that shape college students and addressing the urgent need to explore ways to deepen their commitment to public service.

Freeman argues that volunteer service is typically unpaid work that generates social benefits, which would otherwise require the allocation of resources4. Wilson and Musick define volunteering as time donated for the benefit of the poor or to solve some community problems5. Wilson proposed a new explanation, believing that volunteer service is a service activity in which individuals voluntarily contribute their time, energy, etc. to benefit others or society without obtaining material rewards6. Volunteer service experience refers to an individual’s past involvement in volunteer activities, with researchers commonly using the duration and frequency of participation as key indicators7. Previous studies have found a link between individual Public Service Motivation and volunteer behavior8. Individuals with volunteer service experience tend to demonstrate a stronger and more sustained willingness to volunteer, showing greater engagement in volunteer activities. The increased time investment further confirms that such individuals possess higher levels of Public Service Motivation9. Researchers have identified a positive correlation between Public Service Motivation and prosocial behavior, with volunteering serving as a tangible expression of these prosocial tendencies. Further studies have shown that college students who engage in volunteer work exhibit more compassionate and ethical behaviors, as well as significant improvements in their interpersonal skills. This suggests that involvement in volunteer service not only nurtures Public Service Motivation but also contributes to the development of positive social behaviors and interpersonal competencies10,11. One possible explanation is that the positive feedback gained from volunteering, such as enhanced interpersonal skills, may reinforce individuals’ motivation to engage in volunteer activities and internalize a sense of Public Service Motivation. This process can create a cyclical pattern, where the benefits of volunteering lead to a deeper commitment to public service, ultimately resulting in a more fulfilling and impactful volunteer experience. Based on this reasoning, the study proposes hypothesis H1: There is a significant positive correlation between college students’ volunteer service experience and their Public Service Motivation.

Self-efficacy, a concept developed by Albert Bandura, refers to an individual’s confidence in their ability to effectively plan and execute the necessary actions to overcome challenges. This psychological construct is a core element of Bandura’s social cognitive theory and has been widely studied in fields such as education, healthcare, and organizational management. Self-efficacy plays a pivotal role in shaping behavior, motivation, and performance across various contexts. It influences how individuals approach tasks, cope with difficulties, and persist in the face of obstacles. Enhancing self-efficacy can lead to improved outcomes and greater success in both personal and professional domains. Social cognitive theory posits that human learning and behavior are shaped by dynamic interactions among individuals, their environments, and their actions. As a central concept in this theory, self-efficacy refers to people’s subjective judgment of their ability to complete a given task, reflecting confidence in their skills and capacity to achieve the task12. Self-efficacy is influenced by several key sources that shape an individual’s confidence in their abilities. These sources include factors that contribute to one’s belief in their capabilities. The most influential of these is mastery experiences, which involve reflecting on past successes and achievements. Social persuasion, where individuals receive encouragement and positive feedback from others, can also significantly enhance self-belief. Vicarious experiences, in which individuals observe others succeeding in similar tasks, further boost confidence in one’s own abilities. Lastly, physiological and emotional states, such as stress and anxiety, can have a notable impact on self-efficacy beliefs. Together, these factors shape an individual’s perception of their capabilities and influence their overall self-confidence. According to Bandura’s self-efficacy theory, an individual’s personal experiences of success and failure are the most crucial determinants in forming self-efficacy13. Successful experiences help individuals develop higher self-efficacy, while failure experiences tend to reduce self-efficacy. This effect is most significant when individuals have not yet formed a fixed sense of self-efficacy. College students, being in a formative stage of developing various concepts, are particularly susceptible to the influence of experiences such as participating in volunteer services, which can shape their self-efficacy. Additionally, Bandura posits that an individual’s emotional state and physiological arousal also play a crucial role in the development of self-efficacy13. After college students participate in volunteer services, they receive either positive or negative feedback from those they help, as well as from society. This feedback can influence their physiological or emotional states, which in turn affects their self-efficacy. In a study by Steward Andrew and Hasche Leslie, involving elderly participants, they found that volunteering has a significant impact on the self-efficacy of older adults14. Similarly, volunteer time is significantly related to self-efficacy, and Bandura believes that the level of self-efficacy will enhance or weaken motivation12,15. Previous studies have shown that self-efficacy can positively predict motivation16. Individuals with high self-efficacy are more likely to choose challenging tasks with enthusiasm, demonstrating greater internal motivation. As such, positive volunteer service experiences can enhance self-efficacy, which in turn strengthens Public Service Motivation. Specifically, by engaging in volunteer services, college students can receive appreciation, praise, and recognition from those they help, as well as from society. This positive feedback boosts their self-efficacy, which fosters a stronger commitment to public service and increases Public Service Motivation. Based on this, we propose the following research hypothesis: H2: Self-efficacy mediates the relationship between college students’ volunteer service experience and their Public Service Motivation.

Moral identity is a psychological construct that reflects the degree to which moral values and principles are integral to an individual’s self-concept. It indicates how closely a person’s sense of self is linked to their ethical standards and moral behavior. Individuals with a strong moral identity are more likely to act in accordance with their moral values, even when faced with challenges or competing interests. Moral identity encompasses two dimensions: internalization, which refers to the extent to which moral values are deeply ingrained, and symbolization, which pertains to the outward expression of these values through behavior and actions17. Existing research has found that college students have higher levels of moral identity and prosocial behavior, and there is a moderate correlation between the two, and even a significant positive correlation18. Individuals with internalized moral identities tend to be highly concerned about out-group members and are more willing to offer help. A meta-analysis has shown that moral identity is a strong predictor of moral behavioral intentions, indicating that those who strongly identify with moral values are more likely to engage in moral actions19. Reed, Aquino, and Levy found that individuals with a strong moral identity tend to view volunteering as a morally meaningful activity. In other words, individuals with higher moral identity are more likely to engage in volunteer services. Those with a stronger moral self-identity also exhibit greater prosocial tendencies in daily life, including a stronger willingness to participate in volunteer work, make charitable donations, and engage in organizational citizenship behaviors20. Public services are a key form of prosocial behavior, and as such, moral identity may be positively related to volunteering. College students’ volunteer service experience, along with their moral identity, has a positive impact on Public Service Motivation. Moral identity is recognized as a significant predictor of prosocial behavior. Individuals with a strong moral identity tend to experience higher autonomous motivation during volunteer service, which increases their willingness to continue helping the same beneficiaries in the future21. Hence, it enhances Public Service Motivation. Since volunteer service is a form of prosocial behavior, and prosocial behavior is significantly related to moral identity, moral identity can positively predict Public Service Motivation. According to Bandura’s social cognitive theory, repeated prosocial behaviors, such as volunteering, can shape self-perceptions, including the moral self-concept. Through positive feedback and ethical reflection during volunteer activities, individuals internalize moral values, which strengthens their moral identity. This enhanced moral identity, in turn, amplifies their commitment to public service. Therefore, college students’ volunteer service experience can influence Public Service Motivation by impacting moral identity. Based on this, this study proposes hypothesis H3: Moral identity mediates the relationship between volunteer service experience and Public Service Motivation. Specifically, volunteer service experience fosters moral identity through ethical engagement and social feedback, which subsequently drives Public Service Motivation.

The research findings indicate that academic self-efficacy is positively correlated with both internalized and symbolic moral identity22. When individuals believe in their ability to successfully perform tasks, they are more likely to internalize the moral standards of the group or organization they belong to. In other words, self-efficacy can effectively promote moral identification and ultimately strengthen individual moral behavior23. Zhao believe that after volunteers receive gratitude and praise from the group being helped, their self-efficacy will improve to a certain extent, and college students will further identify with the meaning of helping behavior, thereby enhancing moral identity24. As a result, it can trigger a enhanced sense of Public Service Motivation. College students’ volunteer service experience may influence their Public Service Motivation by shaping their self-efficacy, which subsequently affects their moral identity. Based on this, this study proposes research hypothesis H4: Self-efficacy and moral identity play a chain mediating role in the relationship between college students’ volunteer service experience and Public Service Motivation.

While self-efficacy and moral identity are well-established constructs, their ‌integrated role‌ within a ‌chain-mediating model‌ to explain the enhancement of PSM through volunteer service experience in a ‌non-Western collectivist culture‌ remains underexplored. Most existing PSM research focuses on public servants in Western contexts, neglecting the crucial population of Chinese college students, who represent the future pillars of public service in a rapidly developing society. This study is based on the theories of self-efficacy and moral identity and aims to analyze the influencing factors, internal mechanisms, and boundary conditions of Public Service Motivation from a psychological perspective. It provides empirical evidence to enhance college students’ Public Service Motivation and offers recommendations for selecting college students with high Public Service Motivation through civil service examinations for roles in the civil service. Specifically, the study addresses four key aspects: First, it explores the impact of college students’ volunteer service experiences on Public Service Motivation, further enriching research on the relationship between these experiences and Public Service Motivation. Second, it examines the mediating role of self-efficacy in the relationship between college students’ volunteer service experiences and Public Service Motivation. Third, it investigates the mediating role of moral identity in this relationship. Finally, it examines the chain mediating role of self-efficacy and moral identity in the relationship between college students’ volunteer service experiences and Public Service Motivation. The hypothetical model is depicted in Fig. 1.

Fig. 1
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Mediation model diagram.

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Research methods

Participants

This study focused on Chinese college students as the research subjects, primarily from Jiangxi and Hunan provinces, using face-to-face or online questionnaires. A total of 1,400 questionnaires were distributed, of which 1,344 were deemed valid, resulting in a response rate of 96%. The reasons for excluding certain data were as follows: (1) Incomplete Responses: 15 questionnaires were excluded due to incomplete answers; (2) Inconsistent Responses: 17 questionnaires were excluded for inconsistencies in responses; (3) Non-serious Responses: 24 questionnaires were excluded due to clearly random or non-serious responses. To ensure the sample’s representativeness, a stratified random sampling method was employed, and the demographic characteristics of the sample were highly consistent with the overall student population. The study involved 737 male participants and 607 female participants. The breakdown of participants by academic year was as follows: 62 freshmen, 403 sophomores, 471 juniors, and 408 seniors. Regarding political affiliation, there were 146 Communist Party members, 1,075 Communist Youth League members, 118 unaffiliated individuals, and 5 members of democratic parties. All participants were between the ages of 18 and 22. All participants voluntarily participated in the study and signed an informed consent form. The project was approved by the Ethics Committee of Nanchang University.

Measures

Based on the items tested by Zheng et al., participants’ involvement in volunteer services was measured using two dimensions: time and frequency, specifically the amount of time and frequency of their participation in volunteer services each semester25. Following the method of Thoits and Hewitt, participants’ involvement in volunteer services was coded based on the midpoint of a specified duration range26. The final coding results were as follows: a code of 0 for those who did not participate in any volunteer service, a code of 10 for 1–19 h of service, a code of 30 for 20–39 h of service, a code of 60 for 40–79 h of service, a code of 120 for 80–159 h of service, and a code of 200 for more than 160 h of service. For frequency, a 7-point scale was used, with 1 indicating no participation, 2 indicating less than one day per month, 3 indicating 2–3 days per month, 4 indicating 1 day per week, 5 indicating 2–3 days per week, and 6 indicating 4 or more days per week. The average of the standardized scores for time and frequency was used as the measure of volunteer service experience7. Higher scores indicate a greater amount of volunteer service experience. In this study, the composite reliability (CR) for volunteer service experience is 0.89, and the average variance extracted (AVE) is 0.80, demonstrating good construct reliability and validity.

Self-efficacy scale: Self-efficacy scale compiled by Schwarzer et al.27. The GSES consists of 10 items, each rated on a 4-point Likert scale, ranging from 1 to 4. Participants were asked to indicate their level of agreement with each item by selecting from options such as “completely incorrect,” “somewhat correct,” “mostly correct,” or “completely correct,” based on their actual circumstances. Higher scores indicate greater self-efficacy. For example, one item reads, “I am confident that I can effectively handle any sudden situations.” In this study, the composite reliability (CR) for self-efficacy is 0.97, and the average variance extracted (AVE) is 0.75.

Moral identity scale: The Moral Identity Scale was compiled by Aquino and Reed and translated by domestic scholars28. It consists of a total of 10 items, each scored on a 5-point scale, with 1 indicating strong disagreement and 5 indicating strong agreement. Higher scores indicate stronger moral identity. For example, “Becoming a person with the characteristics of honesty and integrity would make me feel good.” In this study, the CR for moral identity is 0.93, and the AVE is 0.57.

Public Service Motivation Scale: The Public Service Motivation Scale compiled by Kim is utilized in this study29. The scale consists of four dimensions: attraction to policy making (APM), commitment of public interest (CPI), compassion (COM), and self-sacrifice (SS). Each dimension comprises four items, totaling 16 items in the scale. Each item is scored on a 6-point scale, where 1 is the lowest score, representing “Strongly Disagree,” and 6 is the highest score, representing “Strongly Agree.” Higher scores indicate stronger Public Service Motivation. For example, “I believe that making the entire society better is clearly much more important than personal achievements.” In this study, the CR for Public Service Motivation is 0.94, and the AVE is 0.50.

Statistical analysis

SPSS 26.0 was used to conduct a common method bias test, descriptive statistics, correlation analysis, and regression analysis. Amos 24 was utilized to analyze the structural equation model to test the mediating effect of self-efficacy and moral identity on the volunteer service experience and Public Service Motivation of college students.

Results

Common method bias test

Harman’s one-way test was used to whether there was a common method bias. The results showed that there were four components with eigenvalues greater than 1 in principal component analysis.The first unrotated component explained 37.72% of the variance, below the 40% threshold, confirming no severe common method bias. This indicates that there was no serious common method bias in this study. For more details, please refer to Table 1.

Table 1 Total variance explanation.
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Confirmatory factor analysis

In order to test the fit of the scale and research model, validity verification was conducted using Amos 24 software. Typically, structural equation models express complex variable relationships through hierarchical or non-hierarchical, recursive or non-recursive structures to present a complete picture of the entire model. This study employed a covariance-based structural equation model (CB-SEM) and conducted confirmatory factor analysis on four variables - volunteer service experience, self-efficacy, moral identity, and Public Service Motivation - using the method of maximum likelihood estimation. The validation results are as follows: the four-factor baseline model has χ2/df= 1.81 (between 3 and 5), GFI = 0.96 (GFI > 0.9), NFI = 0.97 (NFI > 0.9), IFI = 0.99 (IFI > 0.9), TLI = 0.98 (TLI > 0.9), CFI = 0.99 (CFI > 0.9), SRMR = 0.03 (SRMR < 0.05), RMSEA = 0.02 (RMSEA < 0.05). Generally, when a model meets more than one indicator, it indicates a good fit of the model30. According to the adequacy requirements of each indicator by Wen et al.31, all indicators of this model meet the requirements, showing good fit and outperforming all other alternative models (three-factor, two-factor, and single-factor models). Therefore, the selected variables in this study demonstrate good discriminant validity. For more details, please refer to Table 2.

Table 2 Confirmatory factor analysis.
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Reliability analysis

Table 3 shows the Cronbach’s alpha coefficients for each variable.

Table 3 Reliability analysis.
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Descriptive statistical results of each variable and correlation matrix between variables

The Table 4 details the mean, standard deviation, and correlation coefficients of the variables. From the data in the table, volunteer experience (r = 0.44, p < 0.01), self-efficacy (r = 0.38, p < 0.01), and moral identification (r = 0.46, p < 0.01) show significant positive correlations. There was a significant positive correlation between volunteer service experience and Public Service Motivation (r = 0.45, p < 0.01). Additionally, self-efficacy (r = 0.40, p < 0.01) and moral identity were significantly positively correlated. Volunteer service experience (r = 0.46, p < 0.01) and self-efficacy were also significantly positively correlated.

Table 4 Descriptive statistical results of each variable and correlation matrix between variables.
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Hypothesis testing

According to the suggestions for testing the mediation effect by Baron and Kenny32, the double mediation effect model was tested, and the results of the test are shown in the Table 5. When p < 0.05, it is considered statistically significant. It is observed that volunteer service experience significantly and positively influences college students’ Public Service Motivation after controlling for gender, educational background, and political status. The total effect is 0.30 (p < 0.001), with a direct effect of 0.14 (p < 0.001), supporting the validity of the main effect hypothesis. Additionally, volunteer service experience positively impacts self-efficacy (r = 0.29, p < 0.001) and moral identity (r = 0.22, p < 0.001) after controlling for the specified variables. Both self-efficacy and moral identity further contribute to Public Service Motivation (r = 0.14, p < 0.001; 0.25, p < 0.001). Furthermore, self-efficacy is shown to have a positive effect on moral identity (r = 0.26, p < 0.001). Upon introducing two intervening variables into the relationship between volunteer service experience and Public Service Motivation, the significant impact of volunteer service experience on Public Service Motivation persists. This suggests that self-efficacy and moral identity partially mediate the relationship between volunteer service experience and Public Service Motivation.

Table 5 Main and mediating effects tests.
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The Bootstrap mediation test method was used to further test the mediation effect, and the Bootstrap Process was used to construct the structural equation model. Model 6 was selected in the Process plug-in to test the double mediation effect of role identification and volunteer service passion. The test results are shown in Table 6.

Table 6 Mediation analysis.
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The confidence interval of the mediating effect test of self-efficacy between volunteer service experience and Public Service Motivation was [0.0258, 0.0586], which did not contain 0. The mediating effect was tested, and Hypothesis 2 was confirmed to be true. The mediating effect accounted for 16.16% of the total effect. Similarly, the confidence interval of the moral identity mediating effect between volunteer service experience and Public Service Motivation is [0.0414, 0.0693], which also does not include 0. The mediating effect of moral identity accounts for 21.14% of the total effect, supporting Hypothesis 3.

Furthermore, the confidence interval of the chain mediating effect path was determined to be [0.0126, 0.0273], which does not include 0. This indicates the existence of the chain mediating effect path, supporting Hypothesis 4. Figure 2 illustrates the detailed parameters of the mediation model.

Fig. 2
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Chain mediation model.

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Discussion

This paper explores the impact of volunteer service experience, self-efficacy, and moral identity on Public Service Motivation (PSM) among college students, using Bandura’s social cognitive theory to investigate the mediating effects. The study seeks to uncover the mechanisms that drive students’ motivation for public service, thereby contributing to the literature on the interconnected roles these factors play in fostering PSM. While existing research has primarily focused on public servants, there is a notable gap in studies examining Public Service Motivation within the college student population33. Consistent with previous findings, we confirm that volunteer service experience positively influences Public Service Motivation, with both self-efficacy and moral identity serving as mediators34. The findings highlight the critical role of self-efficacy and moral identity as psychological constructs that promote Public Service Motivation in college students with volunteer experience. This study significantly contributes to our understanding of the factors influencing Public Service Motivation and provides clarity on the mechanisms through which volunteer service experience shapes this motivation.

While previous studies have established that volunteer service experience can enhance Public Service Motivation9, this research is the first to demonstrate the significant roles of self-efficacy and moral identity through their mediating effects. This finding expands the scope of Public Service Motivation research, especially within the context of college students. It not only provides a novel explanatory framework for understanding the connection between volunteer experience and Public Service Motivation but also suggests avenues for future research to investigate and validate other potential mediating variables. Furthermore, the study highlights that engaging in volunteer service can help college students develop a strong commitment to public service35. One possible explanation for this phenomenon is that college students who actively engage in volunteer work gain a clearer understanding of their personal values and goals through various social interactions, which in turn ignites their passion for public service. Additionally, individuals with volunteer service experience tend to exhibit a greater willingness to engage with diverse groups and show increased care and respect for others compared to those without such experience36. This contributes to the development of altruistic tendencies in individuals. This enhanced social interaction and empathy fostered through volunteer service can have a positive impact on the formation of a person’s altruistic values and behaviors.

Expanding on Bandura’s social cognitive theory, our research confirms that positive volunteer experiences can significantly enhance individuals’ self-efficacy. This increased self-efficacy, in turn, strengthens their motivation to engage in public service initiatives. Through meaningful volunteer work, individuals not only develop a greater belief in their own abilities but also cultivate a deeper drive to contribute to society’s betterment. This positive cycle of self-efficacy and motivation plays a crucial role in fostering a culture of altruism and community engagement. These findings align with previous research, which suggests that individuals with higher self-efficacy are more likely to pursue altruistic and public-focused careers37. Our results further align with Cherian and Jacob’s assertion that self-efficacy is a key driver of motivation across different contexts, including volunteering16. Self-efficacy plays a crucial role as a mediator between volunteer service experience and Public Service Motivation. By enhancing self-efficacy, volunteer experiences indirectly contribute to fostering Public Service Motivation among college students. This finding underscores the importance of self-efficacy in understanding how volunteer service influences individuals’ motivation for public service. Our study’s results align with prior research and offer insight into the relationship between self-efficacy and volunteer service experience, as well as its impact on Public Service Motivation. Through engaging in volunteer service, college students gain positive, firsthand experiences that directly influence their self-efficacy levels38. As individuals gain confidence and a sense of accomplishment from their volunteer experiences, their self-efficacy increases, which, in turn, contributes to the development of their personal skills and capabilities. This heightened self-assurance and positive outlook significantly bolster their motivation toward public service. The study highlights the crucial role of self-efficacy in bridging the gap between volunteer service experience and Public Service Motivation. Therefore, when selecting government talent, it is important to consider candidates’ levels of self-efficacy. Higher self-efficacy is closely linked to stronger Public Service Motivation among college students, making the evaluation of self-efficacy an essential element in the assessment process for civil service applicants.

Moral identity plays a vital role in connecting volunteer service experience to Public Service Motivation, acting as a “black box” that partially mediates the relationship between the two. Specifically, college students’ volunteer service experience enhances their Public Service Motivation by cultivating their moral identity. The significance of moral identity in shaping individuals’ commitment to public service, as highlighted in previous research, is a central concept in understanding this process39. Understanding the interplay between moral identity, volunteer service experience, and Public Service Motivation is crucial when selecting college students for government roles. A robust moral identity is strongly associated with higher levels of Public Service Motivation, highlighting the importance of effectively assessing moral identity in civil service applicants. Moreover, as Aquino and Reed suggest, the development of volunteer service is deeply rooted in social moral norms and a focus on vulnerable groups, reflecting a strong moral orientation that drives altruistic behavior17. This emphasis on social care and moral values can transform individuals’ moral identity from symbolic to intrinsic, broadening their sense of moral responsibility beyond personal interests to encompass society at large. This expansion of moral care can significantly enhance individuals’ public service motivation, fostering a deeper commitment to community service. Essentially, moral identity is crucial in shaping college students’ understanding of professional ethics in public service, thereby boosting their motivation to contribute to the greater good. However, our study extends beyond the work of Perry et al.36by demonstrating the dual mediating role of moral identity. While previous studies have explored moral identity as a predictor of prosocial behavior17,20, our findings indicate that moral identity is also shaped by self-efficacy, suggesting a reciprocal relationship in which volunteer experiences not only enhance self-efficacy but also strengthen individuals’ moral self-conception, ultimately leading to greater Public Service Motivation.

Our results must be interpreted within China’s sociocultural and institutional framework. Confucian values, such as the emphasis on social harmony and collective responsibility, likely amplify the mediating role of moral identity in shaping PSM. For instance, volunteer service in China is not merely a personal choice but a societal expectation reinforced through state-led initiatives like the ‘Social Practice Credit System.’ This institutionalization of volunteerism creates a unique environment where moral identity becomes central to students’ self-concept, distinguishing our findings from studies in individualistic cultures. Future cross-cultural research could test whether moral identity’s prominence in PSM pathways is moderated by collectivist norms or state policies. By incorporating psychological factors such as self-efficacy and moral identity, this paper enriches the explanatory model of Public Service Motivation, addressing the limitations of studies that primarily focus on social factors or external motivations. Through an exploration of these psychological mechanisms, the study provides a more comprehensive theoretical framework for understanding why and how volunteer service enhances Public Service Motivation among college students. This highlights the critical role of self-efficacy in shaping Public Service Motivation via moral identity. Drawing from moral identity theory and the self-motivation hypothesis, the study demonstrates that university students enhance their self-perception and cultivate a more positive self-image through voluntary service activities. Motivated by the internalization of moral identity, they expand their moral responsibility, prioritize the collective welfare of the public, and develop a self-driven commitment to public service. In striving for an ideal moral state, they are deeply invested in promoting the common good and nurturing a genuine passion for community service. Our findings offer actionable strategies for stakeholders: Universities should pair volunteer programs with reflective practices to strengthen moral identity and design roles that build self-efficacy. Policymakers should reform the Social Practice Credit System to prioritize quality outcomes and integrate PSM assessments into civil service recruitment. NGOs can enhance engagement by aligning volunteer roles with participants’ skills and regularly communicating societal impact.

Conclusion

In conclusion, this study demonstrates that volunteer service experience positively influences college students’ Public Service Motivation through a chain mediation of self-efficacy and moral identity. By engaging in volunteer activities, students not only build confidence in their abilities but also strengthen their moral self-concept, both of which are crucial for fostering a commitment to public service. These findings highlight the significant role of experiential learning and psychological growth in shaping altruistic motivations.

However, there are several limitations to this study that must be addressed. First, the research sample was limited to college students from Jiangxi and Hunan provinces in China, aged 18–22, which may restrict the generalizability of the findings to other regions, age groups, or cultural contexts. Second, the data were collected at a single time point, which precludes establishing causal relationships and only allows for the identification of correlations. Lastly, the use of self-reported questionnaires may introduce social desirability bias, potentially affecting the objectivity of the results.

For future research, we recommend expanding the participant pool to include individuals from diverse regions, age groups, and social backgrounds to improve the generalizability of the findings. Additionally, utilizing multi-time point data collection could help establish causal pathways among variables and clarify underlying mechanisms. Incorporating interview or observational data may further reduce self-report bias and deepen our understanding of the dynamic interaction between moral identity and self-efficacy. We also advocate for mixed-methods approaches to explore qualitative dimensions of volunteer service experience, such as the type of volunteer work, perceived impact, and emotional engagement, which could provide richer insights into the mechanisms linking volunteerism to Public Service Motivation. To address methodological limitations, future studies should prioritize longitudinal designs (e.g., tracking students’ Public Service Motivation and career choices post-graduation) and behavioral measures (e.g., documenting actual participation in public service initiatives). Such approaches would strengthen causal inferences and reduce reliance on self-reported data40.