To explore issues related to community-driven power-building efforts to improve population health, the Roundtable on Population Health Improvement of the National Academies of Sciences, Engineering, and Medicine hosted a virtual public workshop, "Community Power in Population Health Improvement", on January 28 and 29, 2021. Participants discussed the different components and dimensions of community-led action around different population health improvement topics such as education, transportation, environmental health, healthy eating, and active living, among others. This Proceedings of a Workshop summarizes the presentations and discussion of the workshop.