Ecosystem-based fisheries management (EBFM) has been extensively discussed but rarely applied to management of fishery resources in the United States. This dissertation research examines a case study of EBFM in Chesapeake Bay through a policy ethnography. Chesapeake Bay offers a unique lens for EBFM: the region is comprised of multiple jurisdictions, state and federal agencies regulating fisheries, competing stakeholder interests, and complex ecological interactions. This study details how Maryland Sea Grant (MDSG) facilitated and coordinated the development of a large-scale, multi-disciplinary scientific infrastructure to develop ecosystem-based science and tools to inform fishery management. It explores the roles of different members of the core community engaged in the EBFM project, successes and challenges faced by the project, barriers to implementation, and the potential for the EBFM project to serve as a policy model for other regions exploring the adoption of EBFM. Ultimately, this research reveals how the EBFM project has changed the ideology of fishery management in Chesapeake Bay and poised the scientific and management community to transition from single-species to EBFM.