"Mayoral takeover" has emerged as a major reform option for struggling urban districts since it was launched in Boston in 1992 and Chicago in 1995. This article examines the design, implementation, and the effects of mayoral-led school systems. Our research addresses issues that are critical to systemwide improvement: Are there variation in how mayors govern their schools? How can mayors "add values" to current school reform efforts in their cities? Have more resources been provided for teaching and learning? Is the public more confident in their city's school system? Are test scores improving? In addressing these issues of student outcomes and management improvement, we highlight lessons learned from our research project's mixed-methods approach, including case studies and statistical analyses using a multiyear database on a purposeful sample of 100 urban districts. (Contains 6 tables and 2 footnotes.)