Performance appraisal is widely recognized as a key human resource practice that supports organizational strategy through evaluating employee performance, delivering feedback, and fostering competence development. Despite its importance, the effectiveness of performance appraisal systems in improving work outcomes has shown inconsistent results across different organizational contexts. This study aims to examine the effect of performance appraisal effectiveness on two critical employee outcomes, employee retention and self-reported performance, by investigating the mediating role of workplace culture. The research focuses on the Indonesian banking sector, where managing talent and sustaining performance are strategic priorities. A quantitative approach was applied using Partial Least Squares Structural Equation Modeling (PLS-SEM) to test the proposed relationships and assess the mediating effects. The data demonstrate that retention and self-reported performance are not directly improved by the efficacy of performance appraisals. Instead, its positive impact becomes significant when mediated by workplace culture, which fosters fairness, trust, collaboration, and open communication. The results emphasize the importance of workplace culture in bolstering management control systems in firms and show how it is a crucial mechanism connecting employee outcomes and appraisal effectiveness.