The National Defense Service Medal is awarded for military service during designated national emergency or armed conflict periods, including the Korean War, Vietnam War, Gulf War, War on Terror, and other conflicts. It is typically awarded automatically to those who served during these periods of conflict or emergency, and no application is required. The medal is a bronze medallion with a blue, white, and red striped ribbon.

The medal may also be awarded posthumously, and bronze service stars may be added to the ribbon for participation in additional periods of national emergency or armed conflict. The National Defense Service Medal is not considered a high-level military decoration but rather a service medal intended to recognize service during times of national crisis.