Introduction. There are few examples of effective cardiovascular disease prevention interventions for South Asians (SAs). We describe the results of a process evaluation of the South Asian Heart Lifestyle Intervention for medically underserved SAs implemented at a community-based organization (CBO) using community-based participatory research methods and a randomized control design (n = 63). Method. Interviews were conducted with 23 intervention participants and 5 study staff using a semistructured interview guide focused on participant and staff perceptions about the intervention’s feasibility and efficacy. Data were thematically analyzed. Results. Intervention success was attributed to trusted CBO setting, culturally concordant study staff, and culturally tailored experiential activities. Participants said that these activities helped increase knowledge and behavior change. Some participants, especially men, found that self-monitoring with pedometers helped motivate increased physical activity. Participants said that the intervention could be strengthened by greater family involvement and by providing women-only exercise classes. Staff identified the need to reduce participant burden due to multicomponent intervention and agreed that the CBO needed greater financial resources to address participant barriers. Conclusion. Community-based delivery and cultural adaptation of an evidence-based lifestyle intervention were effective and essential components for reaching and retaining medically underserved SAs in a cardiovascular disease prevention intervention study.