This book chapter focuses on the role of political leadership and entrepreneurship in establishing early legitimacy for and confidence in a reform agenda in Philadelphia’s public school system between 2001 and 2007. The reforms, led by School Reform Commission Chair James Nevels and CEO Paul Vallas, included radical departures from the traditional management and governance of a large urban school district. Taking advantage of the dramatic changes in the policy environment, due to the state’s takeover of the system and to NCLB, Nevels and Vallas took the system in directions never tried before. They opened up new kinds of partnerships with blurred boundaries between the central office, community organizations, and diverse private providers, and they demonstrated the power of combining centralized and decentralized approaches to improving instruction and student and school performance. The case of Philadelphia shows the opportunities afforded public sector entrepreneurs during times of uncertainty and flux.