This paper describes development, over a five-year period, of the Hunter Region Health Promoting Schools Project in New South Wales (NSW), Australia. The project implemented the principles and philosophy of the Health Promoting Schools concept and evaluated its effectiveness using a randomized controlled trial involving 22 public secondary schools. An overview of the preliminary intervention model based on the health promoting schools philosophy and trialed in a pilot study is provided. The authors also outline barriers to, and difficulties in, implementing the philosophically based intervention model in the secondary school setting. The current intervention approach, which evolved over five years, is described in relation to the roles played by project team members and school communities. In addition, the authors outline guiding principles arising from the new approach which facilitated adoption of health promotion strategies in secondary school settings.