McCarthy joined the United States Air Force in March 1951, and served for twenty-one months until the end of 1952, as an enlisted man.Leo T. McCarthy, Oral History Interview, California State Archives, 1995–1996, Page 11 He was in an intelligence unit at the Strategic Air Command and was stationed at Lake Charles, Louisiana for seventeen months. While at the Strategic Air Command, he spent a few weeks deployed to Saudi Arabia taking part in a mission to simulate the start of World War III. He also served in the United States Air Force Reserves for a few years.
