This qualitative study examined dual immersion teachers' identities as they engaged in policy implementation within their school, collaborating in professional learning communities (PLC) with one-way immersion teachers. Data derived from participant observation, interviews, and interpersonal process recall were analyzed through a theoretical lens blending communities of practice theories with theories on identity formation. Findings suggested that the requirement to collaborate across instructional contexts helped the dual immersion teachers to form strong and unique identities that sometimes conflicted with the requirements of their PLC work. The dual immersion teachers' identities were shaped by their roles in the dual immersion program working with ELL students and by their work on PLC teams, and they often felt misunderstood by their colleagues who were not dual immersion teachers. This study has implications for leadership practice and policy research, suggesting that teachers' identities can impact on their engagement with school policies.