Teachers' identities as writers and language users can have an important impact on their pedagogical practices. As the population of writing teachers becomes increasingly diverse, the development of teachers' identities is an important but under-researched topic. This study examines how three prospective teachers from varied linguistic and cultural backgrounds constructed new identities through a multi-draft literacy autobiography project. We trace how these teachers' identities changed and developed across the drafts of their literacy autobiographies, how their identity construction was mediated by the feedback they received, and how their language and literacy identities related to their emerging professional identities as prospective writing teachers.