He attended Paseo High School, Kansas City Junior College, and Washington University in St. Louis, before enrolling at the United States Naval Academy.

Long graduated from the Naval Academy in 1943, served on the battleship USS Colorado in the Pacific and entered the submarine service after World War II.

He served as the principal executive of President Ronald Reagan's fact-finding committee, the Long Commission, that investigated the 1983 Beirut barracks bombing attack that killed 241 United States Marines.

He joined the Defense Policy Board in 1984, and was a part of the Advisory Committee on Command and Control of Nuclear Weapons, chaired by Jeane Kirkpatrick.

Long married Sara Katherine Helms on August 28, 1944, in Jacksonville, Florida.