Five U.S. Army generals have held the rank of five-star general, beginning in 1944: George Marshall, Douglas MacArthur, Dwight Eisenhower, Henry Arnold and Omar Bradley. Arnold also became the U.S. Air Force's only five-star general when his title was redesignated as "general of the Air Force" in 1949.
https://www.reference.com/government-politics/five-star-generals-u-s-history-b2d32c4845fed1cf