This study aims to examine the influence of job characteristics and psychological capital on organizational commitment among Generation Y and Z employees, while also investigating the mediating role of Organizational Citizenship Behavior (OCB). Adopting a quantitative approach, data were collected through a survey of 200 respondents in Makassar City using purposive sampling, with measurement based on a Likert-scale questionnaire and analyzed באמצעות Structural Equation Modeling (SEM) using SmartPLS 4.1. The findings reveal that job characteristics exert a positive effect on both organizational commitment and OCB, whereas psychological capital significantly influences OCB but does not have a direct effect on organizational commitment. Furthermore, OCB demonstrates a significant positive effect on organizational commitment and serves as a partial mediator in the relationships between job characteristics and organizational commitment, as well as between psychological capital and organizational commitment. The results of the PLS-MGA analysis indicate no significant differences between Generation Y and Z in the structural relationships, suggesting a convergence in work-related behavioral patterns across these generational cohorts. This study contributes to the literature by integrating job characteristics, psychological capital, and OCB within a unified framework to explain the formation of organizational commitment, highlighting the pivotal role of OCB as a behavioral mechanism in strengthening employee attachment. The findings also provide strategic implications for organizations in effectively managing a multigenerational workforce to enhance engagement and overall performance.