Despite widespread acknowledgment of the power of professional collaboration, the norm in most schools is teachers working in isolation. Our study examined the impact of multiple layers of professional collaboration intentionally integrated into a one-year preservice teacher education program working in two elementary schools. Analysis of 23 teacher candidates' written reflections, focus group interviews, and classroom observations indicated that supported by collaboration with colleagues, they developed the skills and commitment to teach each student for understanding. Based on our research, we propose a shift in teacher education toward collaborative inquiry about teaching and learning within school/university partnerships.