The aim of this study was to describe the trajectories of teacher leadership development by investigating the interaction between teachers' perceptions and practices of leadership at different career stages. A case study design was adopted. Data were collected from four primary school teachers in China through narrative-style, semi-structured interviews, storylines and observations. The results showed that teachers' perceptions and practices of leadership changed and interacted over time, shaping the trajectories of teacher leadership development. Three leadership development trajectories, influenced by various personal and contextual factors, were identified: perception-driven, bumpy and practice-driven. Adopting an insider's perspective, this study theoretically contributes to the knowledge of teacher leadership by describing and categorizing the dynamic changes in teachers' perceptions and practices of teacher leadership. Moreover, this study has revealed how the interaction of teacher perceptions and practices shapes teacher leadership development. The implications for facilitating teacher leadership development are discussed.