Adverse childhood experiences, or ACEs, may be mitigated by trauma-informed social environments-programs, services, systems, communities-that offer responses to trauma that promote healing, recovery, and resilience. However, there is currently little empirical evidence to support the use of specific approaches to do so. Guided by a population health perspective, this paper describes a participatory community change process in response to ACEs that seeks to build a resilient, trauma-informed community in Pottstown, PA. We examine the initial implementation phase of this change process, centered originally on the education sector and the social and behavioral health services sector, and then eventually expanding to 14 community sectors across two years. A variety of data sources and methods are used to track individual and organizational processes, as well as service system network processes. A central feature of this research is the use of data to generate hypotheses rather than test them. Data were also used to guide understanding and decision-making during implementation. The results show that moving forward the community is well-positioned to establish stronger inter-agency and system supports for trauma-informed practice in the service system and in the broader community. We discuss results for their implications for building resilient, trauma-informed communities.