Increasingly, school-based partnerships have been tied to education reform and the entrance of new private capital into the PK-12 sector. As a result, what may have been an at-will school-business partnership in the 1980s may today resemble an embedded multi-partner arrangement around professional development, teacher evaluation, or turnaround support. From curriculum to practice, and from human resources to operations, the notion of a simple YMCA after school partnership is being replaced by a new wave of collaborations focused on school improvement, integration, and scalability. The purpose of this investigation is to consider the historical context of public-private PK-12 partnerships and elucidate how recent policies emphasizing—sometimes mandating—collaboration between schools and outside agencies can lead to benefits and challenges for PK-12 leaders at the site level. A major challenge to school leaders is that they are relatively unfamiliar with managing partnerships in general, which leaves them even more unprepared to deal with new arrangements that are complex and reform-driven (Bennett & Thompson, 2011). This investigation introduces a new conceptual framework for understanding the environment in which school partnerships exist today. By coupling sources from a multitude of cross-disciplinary fields, such as urban studies, business, nonprofit management, and organizational theory, an effort is made to explain the emergence of this new system from both a historical and theoretical perspective. Further we introduce a proposed PK-12 Blended Capital Typology and methodology for analyzing how decision-making and accountability is shared between partners in these arrangements. Through a single sample case, our goal is to emerge with themes that will support additional research using this framework.