This study explores how six school leadership teams in a rural district in California responded to professional development (PD) designed to strengthen leadership practices and organizational conditions in schools for improving teaching and learning. Specifically, the PD was intended to address the problem of practice identified by the schools: teachers needed to learn to work in new ways to support students in meeting the Common Core State Standards (CCSS). Researchers used design-based implementation research (DBIR) to understand the connection between the design and implementation of the PD model and the impact on participating schools. Findings suggest that in developing PD programs, three challenges need to be addressed in designing experiences for educators that strengthen their capabilities to lead instructional improvement: maintaining the connection between organizational processes and instructional practice; approaching school leadership team collaboration as joint work; and utilizing a developmental approach to improvement. The article concludes by exploring the potential of DBIR for designing and refining models for school leaders' professional learning.