Student teachers who previously have gained academic knowledge or vocational skills often find it challenging to transform content knowledge into teaching activities that contribute to their future secondary students’ learning. Student teachers express a need for pedagogical tools, time to practice, and opportunities for reflection. Previous research has shown that this can be achieved through micro-teaching, which in our interpretation implies that student teachers practice teaching 1) with a limited subject-specific content 2) for a limited amount of time 3) in a low-stakes situation. The aim of this study is to investigate in what ways micro-teaching can support student teachers in designing and conducting subject-specific and pedagogical teaching activities. Our research method is inspired by action research, and conducted in four steps. The first step is to carefully plan how to implement micro-teaching for student teachers in our own teaching. The second step is the implementation. In a third step, we evaluate student teachers’ experiences from conducting micro-teaching through a survey and individual interviews. The fourth step involves analyzing the results, and adjusting our initial plan for implementation of micro-teaching, if needed. Together, these four steps make up the first cycle. We plan to conduct a second cycle before the research questions can be answered. At the time of writing, we are conducting a first cycle in different subjects. Since the study is still in its infancy, there are no results to report, but we expect to find both similarities and differences between the different subjects in how micro-teaching can support student teachers in transforming existing content knowledge into teaching activities.