Comprehensive School Physical Activity Programs (CSPAP) are designed to provide expanded opportunities for physical activity beyond regularly scheduled physical education time-including before, during, and after school, as well as at home and in the community. While CSPAPs are gaining support, currently there are no models for designing, implementing, and assessing these programs. This two-part article presents a new CSPAP curriculum model called Health Optimizing Physical Education (HOPE) that can be used to help P-12 students acquire knowledge and skills for lifelong participation in physical activity. Part 1 discusses the need for the HOPE model, presents its theoretical foundation, and describes eight strands that could be included in such a comprehensive school program. Part 2, next issue, will discuss the knowledge base needed by teachers for conducting effective HOPE programs, offer some strategies for preparing and developing HOPE teachers, and identify some of the many other professionals that HOPE teachers must collaborate with to achieve the overall learning objectives. (Contains 1 table and 1 figure.) [To access Part 2 of this article, see EJ1013296.]