In this study, we seek to conceptualize a theory of emerging teacher leadership, with a specific focus on how pre-service teachers' identity shifts as they move through teacher preparation programs. We theorize the requisite knowledge, skills, and disposition for teachers at different stages of teacher leader development and examine catalytic experiences that facilitate leadership development for pre-service teachers. While pre-service teachers are often solely seen as inexperienced learners, in reframing the way we view pre-service teachers, the opportunity emerges to build on their assets and capacity as teacher leaders.