Since 2002 the Initial Teacher Education Program at the Ontario Institute for Studies in Education, University of Toronto, has run a series of professional learning partnership projects between university instructors and K-12 educators. The Inquiry Into Practice Series, based on a collaborative inquiry approach, has strengthened the commitment to program principles and benefited the participants by deepening understanding about a range of educational questions and issues and improving practice. In this article we review key features and principles of this multi-year initiative and discuss challenges, lessons learned, and outcomes. We also provide reflections regarding the importance of high quality professional learning models that support teaching and learning and that are responsive to changing and complex educational pressures and contexts both in higher education and K-12 education.