In the past decade, the Canadian system of postgraduate medical education has been transformed with the implementation of a new approach to competency based medical education called Competence by Design. The Royal College of Physicians and Surgeons of Canada (Royal College) developed an approach to time-variable competency based medical education and adapted that design for medical, surgical, and diagnostic disciplines. New educational standards and entrustable professional activities consistent with this approach were co-created with 67 specialties and subspecialties, and implementation was scaled up across 17 universities and over 1000 postgraduate training programs. Partner engagement, systematic design of workshops to create discipline specific competency-based standards of education, and agile adaptation were all key ingredients for success. This paper describes the strategies applied by the Royal College, lessons learned regarding transformative change in the complex system of postgraduate medical education, and the current status of the Competence by Design initiative. The approach taken and lessons learned by the Royal College may be useful for other educators who are planning a transformation to CBME or any other major educational reform.