Common Core represents a shift in content-area literacy instruction, broadening from a narrow focus on generalizable skills to also include a disciplinary perspective of literacies specific to the specialized language and habits of thinking within particular subjects. This requires teachers to be knowledgeable in their content and possess competence in pedagogical practices that allow them to scaffold their students' literacy development within these disciplines. We examined how the implementation of a Disciplinary Literacy Project into a content-area literacy course influenced preservice secondary teachers' disciplinary literacy practice. The findings suggest structured inquiry into disciplinary communities enhances preservice teachers' understanding of disciplinary literacy, but this knowledge is not easily transferred into classroom instruction. Implications for future research on disciplinary literacy models and preservice teacher preparation are discussed.