This study aims to enhance proactive knowledge sharing among employees, explore facilitators and barriers, and help managers understand their impact on subordinates' knowledge sharing behaviors. A quantitative survey analyzed 547 valid samples from Chinese enterprises to test hypotheses. (1) Servant leadership positively influences employee knowledge sharing behavior; (2) Servant leadership positively affects core self-evaluations; (3) Core self-evaluations positively impact knowledge sharing behavior; (4) Core self-evaluations partially mediate the relationship; (5) Individualism strengthens the positive effect of servant leadership on core self-evaluations; (6) Individualism enhances the positive effect of core self-evaluations on knowledge sharing behavior; (7) Individualism weakens the direct positive effect of servant leadership on knowledge sharing behavior. Servant leadership directly and indirectly promotes knowledge sharing through core self-evaluations. Individualism amplifies these effects but weakens the direct influence of servant leadership. The findings extend empirical research in the Chinese cultural context, enhancing understanding of the relationship between leadership behavior and employee knowledge sharing, while expanding research boundaries. They also offer insights for managers to optimize leadership practices and improve employee self-evaluations, thereby fostering knowledge sharing and enhancing organizational competitiveness.