Cooper was commissioned into the United States Marine Corps prior to the attack on Pearl Harbor. During World War II he served in the Pacific on the USS Pennsylvania (BB-38), and then was recalled to active duty for the Korean War, resigning his commission as Lieutenant Colonel in 1956. He received a bachelor's degree in political science from Stanford University and, in the mid-1960s, a master's degree in history from the University of California, Riverside.
In 1976, Cooper founded the American Pistol Institute (API) in Paulden, Arizona (later the Gunsite Training Center). Cooper began teaching shotgun and rifle classes to law enforcement and military personnel as well as civilians and did on-site training for individuals and groups from around the world.
Cooper died at his home on the afternoon of Monday, September 25, 2006 at the age of 86
eBook To Ride, Shoot Straight, and Speak the Truth