Estimate the number of full-time equivalents (FTEs) needed to fully implement Foundational Public Health Services (FPHS) at the state and local levels in the United States. Current and full implementation cost estimation data from 168 local health departments (LHDs), as well as data from the Association of State and Territorial Health Officials and the National Association of County and City Health Officials, were utilized to estimate current and "full implementation" staffing modes to estimate the workforce gap. The US state and local governmental public health workforce needs at least 80 000 additional FTEs to deliver core FPHS in a post-COVID-19 landscape. LHDs require approximately 54 000 more FTEs, and states health agency central offices require approximately 26 000 more. Governmental public health needs tens of thousands of more FTEs, on top of replacements for those leaving or retiring, to fully implement core FPHS. Transitioning a COVID-related surge in staffing to a permanent workforce requires substantial and sustained investment from federal and state governments to deliver even the bare minimum of public health services.