PhenomenonClinician-educators (CE) are physicians who fill a unique role within academic medicine, as they are responsible both for patient care and for training future physicians via teaching, curricular design, and creation of educational scholarship. Development of a strong professional identity as an educator leads to greater career satisfaction and a higher likelihood of staying in academic medicine. However, little is known about how this identity develops, especially in the training environment where there are competing pressures to develop as a clinician and researcher. This study aimed to explore professional identity formation in residents and fellows interested in becoming educators. Approach: We used a longitudinal, qualitative approach to investigate professional identity formation in residents and fellows participating in the Clinician-Educator Training Pathway. The longitudinal nature allowed us to temporally explore which aspects of the program and experiences acted as barriers or facilitators of professional identity formation as a CE. Our study used the social cognitive career theory (SCCT) Career Choice Model, which considers contextual influences in addition to the three variables of self-efficacy beliefs, outcome expectations, and goals. Findings: We found that participants shared a common goal of building self-efficacy as an educator. Participants took actions to engage more deliberately in formal and informal teaching and acting as an educator by giving learner feedback, developing curricula, and consuming and conducting educational research, all of which increased self-efficacy as educators. At the beginning of the program, participants were unclear of the roles and trajectories followed to become CEs. Engaging with a community of CEs clarified pathways and presented role models that could be seen as possible selves. This study also elucidated contextual influences relating to personal factors, career opportunities, and potential for advancement that mediated the goals and actions taken by participants to become educators. Insights: This study demonstrates that the SCCT Career Choice Model provides an excellent framework for understanding professional identity formation in future educators. Our participants built self-efficacy, formed outcome expectations, and set goals and took specific actions toward the goal of becoming an educator. Participants tested the various role model attributes as possible selves to see how those would be effective in their own career. Reflection on expectations, career goals, and self-efficacy as a clinician and an educator can assist in identity formation as a CE and can assist those designing CE training programs to better support identity formation in their participants.