The "CORE Districts" (referred to hereafter as "CORE") is a nonprofit organization created in 2010 to foster collaboration between eight of California's largest districts. In 2018-19, "CORE" provided a range of supports to participating districts, including programs to support multiple levels of district and school leaders in developing improvement capability and coaching for school-based improvement leaders and Local Improvement Teams. This case examines the structures, processes, and organizational culture at the heart of a California district--Garden Grove Unified School District (GGUSD)--that has seen steady improvement.