CONTEXT: Public health fellowship programs play a vital role in strengthening the workforce across state, tribal, local, and territorial (STLT) public health agencies. PROGRAM: The US Centers for Disease Control and Prevention's Epidemic Intelligence Service (EIS) and Laboratory Leadership Service (LLS) fellowships provide structured opportunities for trainees to be placed within STLT public health agencies, where they are intended to contribute directly to essential public health functions. Through these assignments, the objective is for trainees to gain practical experience while STLT public health agencies benefit from additional capacity and public health expertise. EVALUATION: Findings from a rapid evaluation showed that EIS and LLS trainees offer crucial support to STLT public health agencies' delivery of Foundational Public Health Services. The trainees also provide surge support during emergency response events, including infectious disease outbreaks and environmental toxins. DISCUSSION: Public health fellowships are a collaborative model of how federal programs can help alleviate longstanding public health workforce challenges, including difficulties recruiting, hiring, and retaining qualified professionals. Integration of trainees into STLT public health agency operations fosters knowledge transfer, strengthens local capabilities, and supports sustained delivery of public health services. Our findings provide additional evidence that public health fellowship programs can serve as essential support for the national public health workforce.