In 2017, Health & Medicine Policy Research Group’s Illinois ACEs Response Collaborative (the Collaborative), the Chicago Department of Public Health (CDPH), and the Alliance for Health Equity (AHE) partnered to establish the Trauma-Informed Working Group (the Working Group) of the AHE, a group of 18 Chicago-area hospitals and health care systems working to become trauma-informed. This report aims to share the learnings of the Working Group. It is our hope that the insights presented here will provide direction for health care institutions and other organizations pursuing TIHC transformation.