The connection between leadership styles and employees’ innovative behavior has been widely investigated. However, none of the studies examine employees’ organizational trust in the public sector. Based on the social exchange theory, this study fills the gap by examining the relationship between transformational and transactional leadership, organizational trust, and innovative behavior of millennial public employees. It also explored the effect of transformational and transactional leadership on innovative behavior mediated by organizational trust. A cross-sectional design was applied by distributing questionnaires to 320 public servants studying at the Universitas Indonesia to obtain their responses. The data were then analyzed using a partial least square structural equation modeling (PLS-SEM). The results showed that transformational and transactional leadership affect the innovative behavior of millennial public employees mediated by organizational trust. This study enriches the knowledge regarding innovative behavior and contributes to public human resources management by enhancing organizational trust. © The Author(s) 2023.