Abstract Background Foundations and public agencies commonly fund focused initiatives for individual grantees. These discrete, stand-alone initiatives can risk failure by being carried out in isolation. Fostering synergy among grantees' initiatives is one strategy proposed for promoting the success and impact of grant programs. We evaluate an explicit strategy to build synergy within the Robert Wood Johnson Foundation's Southern Rural Access Program (SRAP), which awarded grants to collaboratives within eight southeastern U.S. states to strengthen basic health care services in targeted rural counties. Methods We interviewed 39 key participants of the SRAP, including the program director within each state and the principal subcontractors heading the program's funded initiatives that supported heath professionals' recruitment, retention and training, made loans to health care providers, and built networks among providers. Interews were recorded and transcribed. Two investigators independently coded the transcripts and a third investigator distilled the main points. Results Participants generally perceived that the SRAP yielded more synergies than other grant programs in which they had participated and that these synergies added to the program's impact. The synergies most often noted were achieved through relationship building among grantees and with outside agencies, sharing information and know-how, sharing resources, combining efforts to yield greater capacity, joining voices to advocate for common goals, and spotting gaps in services offered and then filling these gaps. The SRAP's strategies that participants felt fostered synergy included targeting funding to culturally and geographically similar states, supporting complementary types of initiatives, promoting opportunities to network through semi-annual meetings and regular conference calls, and the advocacy efforts of the program's leadership. Participants noted that synergies were sometimes hindered by turf issues and politics and the conflicting perspectives and cultures of participating organizations and racial groups. Inadequate funding through the SRAP, restricting program involvement to only a few needy counties, and instances of over- and under-involvement by the program's leadership were sometimes felt to inhibit synergies and/or their sustainability. Conclusion Participants of the SRAP generally perceived that the SRAP's deliberate strategies yielded synergies that added to the program's impact.