This mixed methods study reports on the outcomes of a professional development model (PDM) developed by a K-12 private school in Beirut, Lebanon, after 3 years of its employment. Specifically, an evaluation of this PDM is provided with special emphasis on its potential of developing teacher leaders at school. The PDM embraces a constructivist approach whereby teachers train colleague teachers and some high school students provide ushering services during professional development events. Data was collected using focus group interviews with teacher trainers, surveying teacher trainees and asking student ushers to describe their most important gain from this model using a single statement. Findings of the study highlight resonant school gains from this PDM and underscore its potential in developing not only teacher leadership but also student leadership. The study provides important implications for professional development program designers.