Community health worker (CHW) programs can act as bridges between patients and health care teams, but the complexity and variability of program components and outcomes make them difficult to evaluate. This evaluation used a realist approach to identify underlying mechanisms and contextual factors associated with successful implementation of a community-placed CHW program affiliated with a primary care practice in the Midwest United States. The analysis identified mechanisms by which stakeholders built trust, self-efficacy, and empowerment to improve patient-centered outcomes and experiences.