In this article, the authors present Edwin Diaz, superintendent of California's Gilroy Unified School District and discuss the common challenges and strategies among those education leaders who take on--and succeed at--the role of change agent and reformer. When Edwin Diaz became superintendent of California's Gilroy Unified School District in 2000, it was one of the lowest-performing districts in Santa Clara County. Three-quarters of its schools had failed to meet their improvement targets on the Academic Performance Index, California's test-based accountability system. Diaz's initial strategy was to realign the district's resources to fund professional development and leadership capacity and hire literacy facilitators. He implemented a top-down management strategy to establish a common language about teaching and learning while engaging administrators and teachers in the work so they could advocate changes among their peers and maintain the delicate balance between central and site decisions. The two fundamental challenges superintendents face as change leaders are overcoming resistance to reform and modifying the district's culture. Many superintendents conceded they did not anticipate the massive effort required to transform the mental models of district personnel and board members so that they could see the district as a system, understand their roles and responsibilities in a new light and increase their expectations of results.