This study focused on teacher perceptions of the long-term impacts of engaging in collaborative action research on professional identity and practice. This qualitative, phenomenological study focused on understanding the lived experiences of 10 teachers before, during, and after engaging in action research. Each teacher was interviewed before engaging in action research, after one year of engaging in action research, and two to four years after completing an action research project. Outcomes revealed that several aspects of teacher identity and classroom practice were changed. In addition, the impact of teacher engagement in action research on the broader educational context is discussed.