Undergraduate students often lack opportunities for active, authentic roles with subsequent transitions to post-graduate training presenting abrupt changes in responsibilities. Service learning, where students contribute in their workplace, can facilitate assumption of active roles earlier in training. We aimed to identify features supporting service learning on primary care clinical placements. We undertook focus groups with third-year medical students participating in primary care placements designed around the concept of service learning. Participants discussed experiences; team roles; responsibilities, and resultant learning impacts of these. Data was thematically analysed. Four themes emerged as features related to effective service learning: (1) responsibility; (2) supervision; (3) working with uncertainty; (4) service learning barriers. Supervised student led clinics were effective in providing opportunities for service and learning simultaneously. Students felt they contributed to patient care through authentic interactions, and this sense of responsibility drove learning. Barriers included setting unrealistic student expectations, inadequate supervision and practice logistics such as constrained room space. This study concludes that authentic clinical experience integrated with responsibility are key features when designing service-led clinical placements, with resultant impacts on motivation, building resilience, managing uncertainty, and developing communication skills. Service learning in general practice settings may help support effective transitions to postgraduate training.