[2] He enlisted in the U.S. Army Air Forces on June 28, 1943, and served as a remote control gun turret repairman until leaving active duty on March 1, 1946.

[1] In 1950, Leaf joined the United States Air Force[1] and served as a F-86 Sabre fighter pilot in the Korean War.

In 1969, he graduated from the Industrial College of the Armed Forces, Fort Lesley J. McNair, Washington, D.C. During the Vietnam War, Leaf went to Thailand in March 1966 and served as operations officer and later commander of the 333rd Tactical Fighter Squadron, 355th Tactical Fighter Wing at Takhli Royal Thai Air Force Base.

[1] Leaf later transferred to USAF headquarters in October 1966 where he served in various capacities in the Office of the Deputy Chief of Staff for Research and Development.

He was then assigned as commander of the 366th Tactical Fighter Wing, Mountain Home Air Force Base, Idaho, and in July 1974 he returned to TAC Headquarters at Langley as the deputy chief of staff for requirements.