We investigated teacher leadership in 18 middle schools in one district engaged in an initiative to scale up Collaborative Strategic Reading (CSR). This mixed-methods analysis found variability in CSR teacher leadership, including the number of hours allotted for release time to support the initiative, the activities teacher leaders enacted, and the support they received. Although findings suggest that the full vision of teacher leadership was difficult to implement at scale, teacher leadership was used to leverage change at several sites. We present a case study of a school that demonstrated collective, shared ownership of both CSR and the teacher leadership model. This study highlights the complexity of defining the expectations and support for a district-funded teacher leader role and raises questions about the need and priorities for the role at every school.