Roy Geiger was born in the United States in 1885. He joined the US Marines and served as a commander in Guadalcana in September 1942.

Geiger was recalled to Marine Corps Headquarters to become Director of Aviation but return to active duty when he commanded the Marine Amphibious Corps on Bougainville. He also led the Marines that invaded Guam (July 1944) and took part in the invasion of Iwo Jima (February-March, 1945) where almost 6,000 Marines were killed.

Geiger also led the III Corps at Okinawa (April-June, 1945) where the Americans suffered 49,000 casualties.

Roy Geiger died in 1947.