The Ohio National Guard comprises the Ohio Army National Guard and the Ohio Air National Guard. The commander-in-chief of the Ohio Army National Guard is the governor of the U.S. state of Ohio. If the Ohio Army National Guard is called to federal service, then the President of the United States becomes the commander-in-chief. The military commander of all forces in the State of Ohio is the Adjutant General, Major General John C. Harris, Jr. is responsible for the command of 17,000 members, preparedness and readiness, installation management, and budget of the Ohio National Guard. The current Assistant Adjutant General for Army, with responsibility for overseeing the Ohio Army National Guard training and operations, is Brigadier General Thomas E. Moore II. The current Assistant Adjutant General for Air is Major General James R. Camp with responsibility for overseeing the Ohio Air National Guard.

The Ohio Army National Guard is a part of the Ohio National Guard and the Army National Guard of the United States Army. It is also a component of the organized militia of the state of Ohio, which also includes the Ohio Naval Militia, the Ohio Military Reserve and the Ohio Air National Guard. The Ohio Army National Guard consists of a variety of combat, combat support, and combat service support units. As of September 2010, its end strength exceeded 11,400 soldiers. Its headquarters is the Beightler Armory in Columbus, Ohio. Many units conduct Annual Training at Camp Grayling, Michigan.