Abstract Background Family caregiver training decreases caregiver psychological burden and improves caregiver depressive symptoms and health-related quality of life. Caregivers FIRST is an evidence-based group skills training curriculum for family caregivers and was announced for national dissemination in partnership with the Veterans Health Administration (VHA) National Caregiver Support Program (CSP). Previous evaluations of Caregivers FIRST implementation highlighted that varying support was needed to successfully implement the program, ranging from minimal technical assistance to intensive assistance and support. However, we do not know the optimal level of support needed to inform cost-effective national scaling of the program. We describe a protocol for randomizing 24 non-adopting VA medical centers 1:1 to a tailored, high-touch implementation support or a standard, low-touch implementation support to test the primary hypothesis that high-touch support increases Caregivers FIRST penetration, fidelity, and adoption. Additionally, we describe the methods for evaluating the effect of Caregivers FIRST participation on Veteran outcomes using a quasi-experimental design and the methods for a business case analysis to examine cost of delivery differences among sites assigned to a low or high-touch implementation support. Methods We use a type III hybrid implementation-effectiveness study design enrolling VA medical centers that do not meet Caregivers FIRST adoption benchmarks following the announcement of the program as mandated within the CSP. Eligible medical centers will be randomized to receive a standard low-touch implementation support based on Replicating Effective Programs (REP) only or to an enhanced REP (high-touch) implementation support consisting of facilitation and tailored technical assistance. Implementation outcomes include penetration (primary), fidelity, and adoption at 12 months. Mixed methods will explore sites’ perceptions and experiences of the high-touch intensification strategy. Additional analyses will include a patient-level effectiveness outcome (Veteran days at home and not in an institution) and a business case analysis using staffing and labor cost data. Discussion This pragmatic trial will lead to the development and refinement of implementation tools to support VA in spreading and sustaining Caregivers FIRST in the most efficient means possible. Trial registration This study was registered on April 8, 2022, at ClinicalTrials.gov (identifier NCT05319535).