The U.S. joint military medical community has an increasing role in collaborative health sector engagement internationally as part of a whole of government approach to successful operations. The military must master the ability to catalyze health sector gains that can be developed by hosts, U.S. Government, and international agencies in both permissive environments and conflict zones. Capacity building is helping a partner develop their own capabilities, standards, and resources to the point of self-sufficiency. Optimal effects will come through understanding the military and civilian health sectors of nations and regions, grasping the importance of health to stability and security, and integrating efforts with global health initiatives. The goal is to cultivate military and civilian relationships that assist host nation-led sustainable health sector effects that result in enduring positive U.S. national security outcomes.