This article explores findings from a two-year study of the Expeditionary Learning (EL) professional development program for teachers. Using case study qualitative methods, we present findings about how EL meets the challenge of preparing teachers to teach in innovative ways. We investigate how EL structures experiential professional development for its teachers, the strengths and challenges of these experiences, and how the experiences affect teachers' implementation of professional development in their classrooms. (Contains 1 table, 1 figure, and 2 footnotes.)