In the context of education, this study examined the relationship between perceiving a transformational physical education (PE) teacher and student’s leisure-time physical activity (PA). Furthermore, we tested the potential mediation role of motivational learning climate, passion and self-determined motivation in this relationship. The sample was composed of 2210 high-school PE students (1145 males, 1065 females) between 16 and 20 years of age. Results of structural equation modeling revealed that the perceived transformational PE teacher–PA outcomes relationship was stronger when students perceived a task-involving climate, when they were harmoniously passionate, and when they were self-determined. We conclude that students’ health-enhancing behaviours could be improved if their PE teachers use transformational teaching style and created a task-oriented learning climate.