He earned a bachelor of science degree in biology from the University of Wisconsin in 1956 and a master of arts degree in education from the Interamerican University of Puerto Rico San Germán campus in San German, Puerto Rico, in 1966.

In August 1956 he was commissioned as a second lieutenant through the Air Force Reserve Officer Training Corps program.

McDonald volunteered for the B-52 program and after completing combat crew training in March 1962, was assigned to the 319th Bombardment Wing at Grand Forks Air Force Base, North Dakota.

After the cease-fire he conducted a series of inspections for the Defense Attache Office in Saigon, Republic of Vietnam, and the Vietnamese air force.

In May 1974 he was assigned to the Concepts Division, Office of the Deputy Chief of Staff for Plans and Operations, Headquarters U.S. Air Force, Washington, D.C.

From August 1979 to February 1981 McDonald was commander of the 320th Bombardment Wing, Mather Air Force Base, California.