Hub-centered improvement networks are emerging as an organizational form that has the potential to empower local educators, families, communities, and students to respond positively to ever-rising ambitions for educational access, quality, and equity in the United States. A problem, however, lies in a disconnect between (a) hub leaders as the linchpins of improvement networks and (b) the lack of a readily indexed research base to inform the study, practice, or evaluation of hub leaders and hub leadership. This article develops a theoretical foundation for such research by juxtaposing hub leadership in improvement networks with district leadership in public school districts. It asserts that differences in the organizational contexts, practical work, and ecological contexts of hub and district leadership are sufficiently stark to warrant investment in research focused specifically on the role and practice of hub leadership. It also frames considerations for such research.