This study evaluates the effectiveness of California’s Whole Person Care (WPC) initiative in coordinating health and social services for Medicaid beneficiaries with complex needs during the COVID-19 pandemic. Projects underway in 26 counties engage Medicaid health plans, medical providers, mental health agencies, social service organizations, and public health agencies in collaborative models of care and payment that target specific population groups with complex needs in each county, including people experiencing homelessness, those transitioning from incarceration, and patients with multiple chronic medical conditions.