Shortly after turning 18, he enlisted in the United States Marine Corps during World War II, serving in the 2nd Marine Parachute Battalion and fighting in the 5th Marine Division on Iwo Jima. He received the Purple Heart twice and was a sergeant by the time he was honorably discharged. Returning to civilian life, he enrolled at Saint Mary's College, before transferring to what is now San Jose State University. He contemplated going to work for the FBI. Graduating in 1950, he instead joined the CIA, where he was part of the first recruit class to receive all of its training at the new Camp Peary. He was active in Korea during the Korean War, training refugees for sabotage missions behind communist lines. He also helped train Chinese Nationalist commandos for missions on the mainland.