This paper explores the impact of an initiative designed to promote trauma resilient communities by mitigating social determinants of health and reducing health disparities through capacity-building partnerships. Nine regional partnerships in Los Angeles County were funded to build community capacity to adapt to and recover from traumatic events through outreach and engagement with community members, training related to the impact of trauma, linkages of community members to existing services, and developing new services for target populations. Primary quantitative and qualitative data on community impact were gathered from agency leads (N = 10), partnership members (N = 136), and community members (N = 42). A convergent sequential mixed methods design (qual → QUAN → qual) was selected to provide both breadth and depth of understanding about the impact of community capacity-building from multiple perspectives. From January 2018 through July 2023, partnerships conducted over 30,000 community capacity-building activities with over 1.4 M community members and created 101,370 successful linkages to resources and services among 12,663 unique community members. Agency leads, partnership members, and community members converged on three main themes describing the initiative's impact: (1) Building more empowered and resilient communities
(2) Normalizing help-seeking and reducing the stigma of mental health
and (3) Connections within partnerships/families and with community members. On average, 82% of partnership members endorsed medium to large positive changes in the impacts identified during qualitative analysis. Future work should examine whether contracting with community-based organizations is an effective approach for health systems to promote health equity.