Background: A systematic adaptation of an evidence-based state health curriculum (Michigan Model for Health™, MMH) was created to enhance physical activity and family engagement materials but retain the core functional elements of the curriculum. Methods: The Framework for Reporting Adaptations and Modifications-Enhanced (FRAME) was used to document the adaptation, which used materials from an evidence-informed physical activity program (Interrupting Prolonged sitting with ACTivity, InPACT). Acceptability, appropriateness, feasibility, and perceived value of the adaptation were assessed by key stakeholders, regional school health coordinators (HCs). Results: A planned, fidelity-consistent adaptation was created in which InPACT resources were integrated into the MMH curriculum, with recommended integrations packaged in a supplemental guide. Training was modified as appropriate. The guide had high acceptability, appropriateness, and feasibility among HCs (n = 17), and 71% of HCs (n = 24) indicated that it had really strong value. Conclusions: Next steps involve implementing the adapted curriculum and evaluating its effects on family engagement, youth physical activity levels, and overall curriculum effectiveness.