It is commonly understood that policy makers make curriculum policy and teachers implement it. Some teachers, however, have been in on the ground floor of curriculum policy development. Driven by events in their life histories and teaching contexts, these teachers develop and teach original course material in their own classrooms. Over time they begin to work collaboratively on further course development, secure organizational support to ensure adequate resources and legitimacy to disseminate these new curricular forms, lobby for course acceptance by educational jurisdictions, and help establish course infrastructure such as teacher professional learning opportunities and textbooks. In other words, in some cases, teachers may participate actively in every stage of policy development and practice. This article discusses the phenomenon of teacher-driven curriculum innovation as a process of individual, social, and political evolution. It describes three cases of secondary-level courses developed by teachers in Ontario, Canada, and formalized in district or provincial policy. In doing so, the article extends the notion of teacher agency from its established arenas of classrooms and schools and into the realm of policy making.