The importance of professional identity development in learning to teach has been highlighted in recent years. The present study examined the process of how English teachers develop a drama teacher role identity upon receiving in-service training on educational drama. The influence of the training was observed by means of interviews, observations, and reflective journals. The analysis, guided by Kaplan and Garner’s (2017) Dynamic Systems Model of Role Identity (DSMRI), produced important hints on the conditions for the formation of a drama teacher identity. The findings indicated that the training program broadened the teachers’ perceived action possibilities and that a teacher’s identification with drama depended on their institutional context, alignment of action possibilities, professional belief system, and self-perception.