Although action research has a history of bridging gaps between research and school practice, challenges emerge when aligning a scientific approach with development work in schools and in collaboration between research and school practice. In this article, we aim to deepen the knowledge on teachers' action research as social learning in collaboration with a research-based PD leader. In this study, we follow two teachers conducting action research in a Swedish upper secondary school, in collaboration with a professional development (PD) leader who is also a doctoral student. Qualitative data have been used to write value-creation stories that illustrate the learning process throughout their collaboration. Our findings show how joint work between the teachers and the PD leader functions as a boundary process where two sets of practices -- classroom and academic -- are coordinated and contribute to the learning process.