In this multi-method case study, the authors explore the success of school reform in Milwaukee Public Schools (MPS), whose school reform combines a portfolio strategy and a managed instruction approach. Portfolio strategy is a term used to describe an approach that decentralizes resources and decision-making to school sites--increasingly in conjunction with the creation of charters and other schools of choice. In this approach, choice among a diverse set of options is a strong element and there is an expectation that choice and market-based accountability will drive improvements in schooling. Managed instruction is an approach that calls for strong district oversight of school and classroom practices, with strong guidance and support for teaching. This strategy is based on the expectation that direction around "best practices" and support for professional development will lead to improved teaching and learning. School Accountability Categories in MPS is appended. (Contains 8 figures, 15 tables, and 19 endnotes.)