Postpartum contraceptive counseling and access are challenging in Nepal’s remote, hilly areas, driving a disproportionately higher unmet need for contraception. Community health workers (CHWs) play an important role in delivering healthcare in difficult to reach places in Nepal, but there is limited evidence on the ideal CHW model and its impact over time. We implemented a pilot program in two rural districts in Nepal where full-time, salaried, and supervised CHWs delivered a bundled reproductive, maternal, newborn, and child health (RMNCH) intervention. This included a person-centered contraceptive counseling component adapted from the Balanced Counseling Strategy. Applying a type 2 hybrid effectiveness-implementation study approach, we conducted a non-randomized pre-post study with repeated measurements and nested qualitative data collection to assess the intervention’s reach, effectiveness, adoption, implementation, and maintenance. This paper describes the postpartum contraceptive outcomes associated with the integrated RMNCH intervention over a five-year period. Compared to the pre-intervention period, we observed a higher ward-level post-intervention postpartum contraceptive prevalence stratified by early postpartum (RR: 2.20; 95% CI: 1.96, 2.48) and late postpartum (RR: 1.70; 95% CI: 1.50, 1.93) periods, after adjusting for district and intervention site. Although we observed high rates of lactational amenorrhea method (LAM) in most intervention sites, the proportion of women who switched from LAM to another effective method was relatively low. Qualitative data indicate that CHWs’ longitudinal engagement enabled them to build trust with participants in their community, which likely contributed to the uptake of modern contraceptive methods. Barriers to modern contraceptive use included fear of side effects, limited autonomy for women, peer influence, and contraceptive unavailability. Implementation barriers included distance, challenging physical terrain, and increased travel times during the rainy season. This study contributes to the implementation research literature on community-based interventions to improve postpartum contraception use and may inform other CHW programs in similar contexts.