Purpose: Volunteer service learning activities, including Student Run Clinics (SRCs), are becoming an increasingly popular extracurricular component of medical education. While there are reports that student clinicians generally enjoy their educational experiences at SRCs, it is not understood how to optimize and measure student engagement in them. To identify key drivers of student engagement a tool was created to measure volunteer experience at the Crimson Care Collaborative (CCC), a primary care SRC. Methods: CCC volunteers were asked to complete an online engagement survey. Cross-sectional survey data were collected for 149 CCC volunteers (53% response rate). Results: Multivariate linear regression showed that overall ‘likelihood to recommend CCC to a friend’ was significantly associated with students’ perception of the clarity of their role within the clinic, frequency of interprofessional interactions, and overall quality of medical education. Students who volunteer more frequently and for longer periods of time had higher engagement scores. Conclusions: Measuring engagement is feasible in volunteer settings. Engagement appears to be dependent on both structural and experiential components. Easily modifiable components of job design (role definition, expected frequency of volunteering), are key drivers of volunteer engagement.