The history of physiotherapy can be seen as a history of boundary conflict, as the profession sought to first establish, then maintain, its distinctive professional identity. Traditional approaches to the sociology of the professions support this, seeing professionalization as an ongoing process of enclosure, encroachment, and conflict. Recent work, however, has emphasized the fluidity and collaborative nature of professionalization projects, and placed more emphasis on interprofessional negotiations and disciplinary coexistence. In this paper, we draw on this work to analyze the harmonization of the independent Mensendieck System of medical gymnastics in Norway, and the emerging state-sponsored physiotherapy system. Our contention is that over the course of the middle decades of the 20th century, advocates of the Mensendieck System and providers of orthodox, biomedically informed physiotherapy, came together and found a way to work collaboratively in a shared space without compromising their distinctive professional identities. We argue that this approach both points to ways we might revisit traditional conflict-based analyses of the history of physiotherapy, while also suggesting new ways of imagining how the profession might change in the years to come.