High Quality Content by WIKIPEDIA articles! The National Guard of the United States is a reserve military force composed of state National Guard militia members or units under federally recognized active or inactive armed force service for the United States. Militia members are citizen soldiers, meaning they work part time for the National Guard and hold a civilian job as well. The National Guard of the United States is a joint reserve component of the United States Army and the United States Air Force and maintains two subcomponents: the Army National Guard of the United States for the Army and the Air Force`s Air National Guard of the United States.