In 2011, President Obama addressed the United Nations General Assembly and urged the global community to come together to prevent, detect, and fight every kind of biological danger, whether a pandemic, terrorist threat, or treatable disease. Over the past decade, the United States and key international partners have addressed these dangers through a variety of programs and strategies aimed at developing and enhancing countries' capacity to rapidly detect, assess, report, and respond to acute biological threats. Despite our collective efforts, however, an increasingly interconnected world presents heightened opportunities for human, animal, and zoonotic diseases to emerge and spread globally. Further, the technical capabilities required to develop biological agents into a weapon are relatively low. The launch of the Global Health Security Agenda (GHSA) provides an opportunity for the international community to enhance the linkages between the health and security sectors, accelerating global efforts to prevent avoidable epidemics and bioterrorism, detect threats early, and respond rapidly and effectively to biological threats. The US Department of Defense (DoD) plays a key role in achieving GHSA objectives through its force health protection, threat reduction, and biodefense efforts at home and abroad. This article focuses on GHSA activities conducted in the DoD Office of the Assistant Secretary of Defense for Nuclear, Chemical, and Biological Defense.