This 5-month qualitative study investigates how one high school English teacher situated students as readers and writers within daily, spontaneous classroom interactions. Specifically, the author draws on positioning theory (van Langenhove & Harre, 1999) as a lens to analyze how the teacher navigated improvised responses during three separate literacy events to position students as engaged readers, capable writers, and members of a writing community. This approach construes that literacy learning is an identity process in which language is a powerful medium. Results from the study suggest that teachers must be sophisticated navigators of improvised interactions to facilitate the process of literacy learning. Vetter offers suggestions to teacher educators about how to implement critical analysis of classroom interactions and improvised responses to improve literacy instruction. (Contains 1 table.)