Purpose: This study examines the influence of Quality of Work Life (QWL), Job Satisfaction, and Transformational Leadership on team member performance in private companies, with Organizational Culture as a mediating variable. It also integrates Social Exchange Theory (SET), Organizational Support Theory (OST), Ability Motivation Opportunity (AMO) Theory, and Resource-Based View (RBV) to explain performance mechanisms. Methodology: Using a quantitative Partial Least Squares Structural Equation Modeling (PLS-SEM) approach, data were collected from 105 employees of Indonesian private companies via purposive sampling. The respondents had at least one year of experience. SmartPLS 3.29 was used for validity, reliability, collinearity, and bootstrapping analyses for hypothesis and mediation testing. Results: QWL has a significant positive direct effect on performance, whereas Job Satisfaction and Transformational Leadership do not. Organizational Culture significantly mediates the effects of Job Satisfaction and Transformational Leadership on performance, but not QWL. Organizational Culture also has a significant direct effect on performance. Conclusions: Performance improvement depends on individual factors and organizational culture, QWL directly affects performance, whereas Job Satisfaction and Transformational Leadership influence it indirectly via Organizational Culture. Limitations: The small sample size, cross-sectional design, and self-reported data limit the generalizability of the findings. Contributions: The study integrates SET, OST, AMO, and RBV, clarifies inconsistent findings, and offers managerial implications for strengthening organizational culture and leadership development.