Graduate education in chemistry typically follows an apprenticeship model, primarily aimed at preparing students for academia; however, the inclusion of teaching within this apprenticeship is not always clear as faculty, students, and other stakeholders do not agree on the need for instructional training. Despite the variability in training, a large majority of chemistry graduate students will be graduate teaching assistants (GTAs) at some point in their education and will hold these positions while conducting research. This discrepancy between hiring graduate students as GTAs and inconsistent inclusion of instructional training indicates a misalignment between the needs of graduate students and the support programs offer. This multiple case study using a sociocultural perspective focuses on chemistry graduate student identity development as researchers and teachers to understand how chemistry graduate students make sense of their roles and intersections of those roles in the context of a first-semester training course which integrates content related to research and teaching. The course incorporates GTA training best practices from the literature and course components designed to support identity development. Qualitative data in the form of interviews were the main sources for analysis. A priori and inductive coding using Thematic Analysis methods revealed patterns in how chemistry graduate students develop as teachers and researchers and how those identities intersect. The results of this study demonstrate the importance of explicitly discussing how and why teaching is relevant in chemistry graduate student education more broadly and that student agency in the structure of such courses is useful for graduate student professional development in chemistry.