This article introduces key concepts of activity theory and expansive learning. Expansive learning builds on the foundational ideas of the cultural-historical activity theory (CHAT). It is a research approach designed for studying the complexities and contradictions in authentic workplace environments. Change Laboratory is a formative intervention method developed for studying workplaces in transition and for stimulating collaborative efforts to design improved patterns of activity. We present concrete examples of formative interventions in healthcare, where good patient care was compromised by the fragmentation of care and disturbances in collaboration between the healthcare experts. This implies that physicians are challenged to develop collaborative and transformative expertise. We present three spearheads into a zone of proximal development, representing opportunities for change of medical expertise: (1) reconceptualizing expertise as object-oriented and contradiction-driven activity systems, (2) pursuing expertise as negotiated knotworking, and (3) building expertise as expansive learning. While medical expertise needs to expand, medical education must also look for ways to evolve and meet the challenges of the surrounding society. We call for adopting an interventionist approach for developing medical education and intensifying collaboration with the practitioners in healthcare units, their patients and target communities.