Following a professional program to ensure qualification for school leadership is a growing trend. However, school leaders have also come to understand and use content from educational programs in widely different ways. There is therefore a need to study how participating school principals experience learning differently within one and the same program. This empirical study uses qualitative methods to examine fourteen compulsory school principals' experiences of how the mandatory Swedish National Principal Training Program contributes to their professional development. The findings show how program elements can be experienced as contributing to professional development of some principals while being experienced as obstacles for others, depending on becoming active or passive driving forces for participants in terms of orientation, reflection, exploration, and interplay. Applying a theoretical framework made it possible to describe and understand their professional development through program participation in a nuanced way. In terms of analytical generalization such knowledge may form the basis for development of school leader programs.