Federal public health agencies face complex challenges that require leaders capable of making strategic decisions, directing emergency response, and advancing crucial health services. Public health leadership skills can be cultivated through leadership development programs. However, limited data are available to guide the development and implementation of such programs. We describe the Centers for Disease Control and Prevention's (CDC's) Future Leaders in Infections and Global Health Threats (FLIGHT) fellowship. In 2019, CDC established FLIGHT to develop emerging leaders capable of addressing infectious disease threats in CDC's international country offices. This 3-year program provided leadership training, international public health practice, and post-FLIGHT employment opportunities at CDC host sites. FLIGHT participants (14 total; 12 graduates) gained valuable international experience and leadership training, contributed to public health emergency responses, and developed scientific leadership skills. We describe program implementation and findings from internal program evaluation activities conducted among participating officers and host sites. FLIGHT faced structural limitations that affected its overall effectiveness. Recruitment challenges stemmed from the program's duration and lack of direct-hire mechanisms, whereas limited cohort sizes restricted scalability and evaluation. Limited host site engagement and misalignment among program design, host site commitments, and post-FLIGHT career pathways further constrained long-term sustainability and effectiveness. Lessons learned from FLIGHT emphasize the importance of aligning program objectives with agency workforce needs, establishing clear career pathways for graduates, and considering evaluation approaches for programs with limited cohort sizes. As FLIGHT sunsets in 2026 amid funding concerns, these findings can guide development of future public health leadership trainings.