The National Academies Roundtable on Population Health Improvement hosted a workshop in February 2022, A Population Health Workforce to Meet 21st Century Challenges and Opportunities. The event, building upon the proceedings from their March 2019 workshop, Dialogue about the Workforce for Population Health Improvement, was further informed by the ongoing COVID-19 pandemic, the effects of climate change, and recent attention to and expenditure on the public health workforce. Workshop discussions explored the scope of work and work settings for public health and population health workers; the state of the workforce including attrition and gaps in specific roles and disciplines; and challenges to training, recruiting, and retaining workers. This Proceedings of a Workshop summarizes the presentations and discussions held during the workshop.