John Loh graduated from the U.S. Air Force Academy at Colorado Springs, Colorado, Class of 1960. From 1990 to 1991 he served as the 24th Vice Chief of Staff of the Air Force, and served as Acting Chief of Staff from September to October 1990 after General Michael Dugan, 13th Chief of Staff, was dismissed by Secretary of Defense Dick Cheney. He retired in 1995 as a U.S. Air Force 4-Star General.