Integrating HIV prevention into the clinical care of people living with HIV has emerged as a priority in the US As part of a cross-site evaluation this study examined the processes by which 15 clinic-based projects implemented interventions funded under the Health Resources and Services Administration's (HRSA) HIV Prevention with Positives (PwP) in Clinical Settings Initiative. We conducted 61 in-depth interviews with researchers and interventionists across the 15 projects. Intervention implementation was feasible assuming several key components were in place: (1) internal leadership to overcome resistance and foster interest and motivation among clinical providers and staff; (2) adequate attention to creating seamless flow between clinic practice and intervention; and (3) ongoing training that met clinician and staff needs as prevention interventions become a regular part of care. Interventions well matched to the clinical environment and the patient populations were feasible and acceptable to health care providers, prevention interventionists, and clinic staff.