This paper describes how one New York City school district uses staff development to change instruction system-wide, discussing the role local school districts play in systemic school improvement and the role of professional development in connecting reform policy to classroom practice. The paper emphasizes the district's sustained attention to school improvement through professional development. The district's improvement strategy includes: (1) a set of organizing principles about the process of systemic change and the role of professional development in that process and (2) a set of specific activities that emphasize system-wide improvement of instruction. Its staff development has distinctively organized professional development models. Organizing principles include: focusing only on instruction; viewing instructional change as a long, multi-stage process; sharing expertise to drive instructional change; emphasizing system-wide improvement; working together to generate good ideas; setting clear expectations, then decentralizing; and promoting collegiality, caring, and respect. Specific professional development models include the professional development laboratory; instructional consulting services; inter-visitation and peer networks; off-site training; and oversight and principal site visits. This project's professional development is kept visible in the district budget, with the district committed to spending a specific proportion of the budget as an expression of the priority it places on professional development. The district uses multi-pocket budgeting to support this effort (orchestrating multiple sources of revenue around one priority to produce maximum revenue for that purpose). Four appendixes present sample agendas, schedules, and forms and a description of one program. (SM)