We conducted a process evaluation of the Shaping Healthy Choices Program, a multicomponent school-based nutrition program, when implemented in partnership with University of California (UC) CalFresh and UC Cooperative Extension (UCCE). There were positive impacts on participating students, but results varied across counties, possibly due to variation in fidelity to the curriculum and implementation of program components. Our evaluation identified the strength of UCCE in delivering nutrition education and a need for additional support and training for building capacity to effect change in school policies, systems, and environment. Because educators throughout Extension are working to integrate programs addressing policies, systems, and environment, our results may have applicability in other Extension programs.