Introduction Many medical schools engage students in health system improvement (HSI) efforts. Evaluation of these efforts often focuses on students’ learning outcomes and rarely considers the impact on health systems, despite the significant commitment health systems make to these efforts. Our study identified and evaluated system-level outcomes of pre-clerkship medical students’ engagement in HSI efforts.

Methods We used an instrumental case study approach to examine the effects of pre-clerkship medical students’ engagement in HSI projects as part of a 15-month experiential curriculum. We extracted data from 53 project summaries and posters completed during the 2017–18 academic year and follow-up survey data collected in May 2019 from physician coaches and health system professionals who mentored students, contributed to these projects, and worked in the clinical microsystems where the projects occurred.

Results We identified three categories and ten indicators of health system outcomes relevant to medical student engagement in HSI. Using these indicators, our evaluation found multiple benefits to the microsystems in which projects occurred. These included achievement of project aims, perceived immediate and sustained project impact on the health system, and development and implementation of projects with aims that aligned with national and health system priorities.

Conclusion Evaluation of HSI curricula needs to include effects on health systems so that program design can optimize the experience for all involved. Our study offers a framework others can use to evaluate system-level effects of project-based HSI curricula and shows several ways in which students’ engagement can add value to health systems.