Issue Addressed: The Western Australian School Health Project (WASH Project) assists schools to develop comprehensive school health promotion programs. During the last two years, the WASH Project has identified a number of key success factors that help improve the quality of the intervention and outcomes that can be achieved in schools. Methods: These key factors have largely been identified by the evaluation of the WASH Project. The WASH Project evaluation includes both qualitative and quantitative aspects. Results: The key factors are organised into three functional groupings: A) negotiating with schools; B) working with schools (implementing); and C) maintaining health promotion in schools. In combination, the key factors optimise conditions to initiate and implement health promotion interventions and, maintain school structural support for school health promotion once external input has been withdrawn. Conclusions / So What: Some of the key factors identified as important to the implementation of the WASH Project and to the longevity of health promotion programs in WASH Project schools may be usefully taken into consideration when planning comprehensive school health promotion programs elsewhere.