Based on the fact that many youth do not meet global health recommendations for physical activity (PA), and that schools constitute an arena in which all children may be reached, PA integrated into school settings is critical. Inspired by the theoretical framework of Gert Biesta and his three domains of education, i.e. qualification, socialization and subjectification, this study examines secondary school teachers' overall perceptions of the purpose of physically active learning (PAL) in secondary school. This is accomplished by using a longitudinal design, and interviewing 12 teachers three times -- before, during, and after a PA school intervention that they organized. The analysis of the teachers statements revealed two main purposes that are related to the domain of qualification, two to the domain of socialization, and none to the domain of subjectification. However, the analysis showed that some perceptions are implicitly related to the domain of subjectification. Our findings correspond with the leading discourse, which highlights the importance of public health and academic outcomes in terms of PAL. We suggest, however, that the aim of implementing PA in schools should comprise all three domains of education, and that teachers must achieve a successful balance between different aims, and make decisions based upon desired results in upcoming pedagogical situations.