Responding to the call for reform in American graduate teacher education programs, the authors of this paper examine the design of a teacher action research-based approach in which teacher inquiry lies at the heart of individual courses and the program as a whole. The authors report on the transformation of program graduates from teachers to teacher action researchers to teachers as agents for systemic change that occurs as teachers conduct a series of teacher action research studies in their classrooms. The interconnected nature of individual courses, the demanding but practical challenges, the substantial investment of time, the commitment to student engagement and achievement, and the changes that occur in the ways in which teachers think about teaching are among the important themes. (Contains 2 tables and 2 figures.)