Teacher leadership is frequently implemented alongside top-down mandates as a way to provide both pressure and support for change. At the same time, the convergence of policy tools with fundamentally different theories of change can complicate and hinder improvement efforts. The purpose of this qualitative case study is to examine one instance where policy tools with divergent theoretical assumptions converge: the use of teacher leadership as a capacity-building tool and high-stakes teacher evaluation, an authority tool with sanctions for poor performance. As such, this study investigates the extent to which these two approaches complement one another to facilitate improvement or whether they conflict in ways that are counter-productive. To understand the interplay of high-stakes teacher evaluation and teacher leadership, I conducted an in-depth case study in one high school. Findings from the study indicate that the school and district supported the teacher leader in building teachers' capacity through high-quality learning experiences. However, the teacher leader's efforts were hindered by the high-stakes teacher evaluation context, which created a risk-averse earning environment and impeded teachers' engagement in the kind of learning needed to change instructional practice. Instead of interpreting the high-stakes evaluation as an impetus to embrace available learning opportunities, teachers focused on complying with top-down policy mandates at the expense of learning.