The U.S. military has a long history of vaccinating service members against infectious disease as a military necessity to protect soldiers and contribute to the overall mission readiness of the force. The coronavirus disease 2019 (COVID-19) pandemic has once again demonstrated the importance of the health and readiness of the force. In this report, the authors examine how the Department of Defense (DoD) COVID-19 vaccination program was developed and implemented, determine how previous DoD vaccination programs influenced those decisions, and identify opportunities to strengthen the departments vaccination program, particularly against emerging infectious diseases, such as COVID-19. They examine the laws and policies that guide the overall DoD vaccination program, study lessons learned from other DoD vaccination programs, and determine the policies for handling medical and administrative (including religious) exemptions. The authors also created an exploratory framework for considering vaccine acceptability-including the key attributes of a vaccination campaign-which could provide an important basis for thinking about how to manage future DoD vaccination campaigns.