This study explored the teacher identity development of Asian teaching assistants (ATA) at a U.S. university. The researchers used a qualitative design with two semi-structured interviews with each of the three participants. Findings suggest that ATAs were unprepared for racial diversity and experienced anti-Asian sentiment in the classroom during the COVID-19 pandemic. They struggled to make sense of the content of the courses they were teaching due to a lack of systematic training. Some constructed teacher identity through a challenging process: moving from being self-doubting, nervous, and frustrated to being comfortable, confident, and even creative. The findings suggest that universities should pay attention to the preparation of international teaching assistants (ITA) for teaching in a multicultural U.S. context with unfamiliar student expectations for teaching and learning.