This paper explores the purposeful use of conceptual and methodological tools provided by Cultural Historical Activity Theory (CHAT) to transform learning cultures and practices within and across diverse clinical learning environments. We describe how Change Laboratory methodology helped clinicians and others who support student, intern, and resident education to make changes collaboratively. A case study in undergraduate medical education shows how this created new forms of medical student placement and a postgraduate study shows how it addressed supervisors' undermining behaviour towards Obstetrics and Gynaecology residents. This empirical work illustrates ways of modifying the classical Change Laboratory process to fit local contexts, resources, and needs. We conclude with lessons learned and future directions for practitioner-researchers who wish to broaden the range of methodological tools they use to transform clinical learning environments.