Objectives:The aim of this study was to explore factors that may influence the formation of professional identity in clinical teachers, specifically during the transition period from practitioner to teacher. Methods: This was a descriptive qualitative study. We used Schlossberg's 4S framework to explore influential factors comprised of the following: situation, self, support, and strategies. This study was conducted in teaching hospitals of a relatively new private medical school in Bali, a province in Indonesia. The participants were 30 clinical teachers who were selected using a maximum variation sampling strategy based on length of work experience, gender, specific educational roles as coordinators, and clinical specialty. Data were derived from three focus-group discussions and 13 indepth interviews. A thematic analysis method was used to analyse the data. Results: The thematic analysis revealed that 12 subthemes related to the 4S framework influenced the development of clinical teachers' identity. It was also shown that reflective ability and community of practice, which was included in the self and strategy factors, respectively, were the two most important factors during the transition period in the development of professional identity. Conclusions: Factors, both within and outside the self, can either support or hinder the formation of professional identity in clinical teachers. We suggest that when faculty development programs are designed, these factors should be incorporated, such as including a community of practice as part of the formal faculty development programs and the development of a teaching portfolio that nurtures reflective practice.