How might members of a large, multi-institutional research and resource consortium foster justice, equity, diversity, and inclusion as central to its mission, goals, governance, and culture? These four principles, often referred to as JEDI, can be aspirational-but to be operationalized, they must be supported by concrete actions, investments, and a persistent long-term commitment to the principles themselves, which often requires self-reflection and course correction. We present here the iterative design process implemented across the Clinical Genome Resource (ClinGen) that led to the development of an action plan to operationalize JEDI principles across three major domains, with specific deliverables and commitments dedicated to each. Active involvement of consortium leadership, buy-in from its members at all levels, and support from NIH program staff at pivotal stages were essential to the success of this effort. The ClinGen JEDI action plan that resulted from our process is a living document and roadmap whose target goals and deliverables will continue to evolve. Here, we offer a transparent account of how a large, multi-site biomedical research consortium achieved this, as well as the challenges and opportunities we encountered on this first step in our journey toward enacting JEDI principles in our sphere of influence. We hope that others seeking to engage in this work will gain valuable insights from our process, experience, and lessons learned.