Robert Keen was born on October 25, 1923, in Florida. He enlisted in the U.S. Army Reserve on June 3, 1942, and entered the Aviation Cadet Program of the U.S. Army Air Forces on November 13, 1942. Keen was commissioned a 2d Lt and awarded his pilot wings on August 30, 1943, and then completed P-47 Thunderbolt training before being assigned to the 61st Fighter Squadron of the 56th Fighter Group in England in January 1944. Lt Keen was credited with the destruction of 6 enemy aircraft in aerial combat, 1 probable, 1 damaged, and 4 enemy aircraft destroyed on the ground while strafing enemy airfields before he rotated back to the United States. After attending gunnery school, Maj Keen served as a fighter pilot at various bases before serving as an F-84 Thunderjet pilot and Commander of the 307th Strategic Fighter Squadron of the 31st Strategic Fighter Wing at Turner AFB, Georgia, from June 1952 to March 1954. He served as Operations and Training Officer for the 407th Strategic Fighter Wing at Malmstrom AFB, Montana, from September 1956 to July 1957, and then attended Air Command and Staff College at Maxwell AFB, Alabama, from August 1957 to June 1958. Col Keen then remained on the staff of Air Command and Staff College from June 1958 to August 1961, followed by attending Army War College at Carlisle Barracks, Pennsylvania, from August 1961 to July 1962. His next assignment was as an Operations Staff Officer with Headquarters U.S. Air Forces in Europe at Lindsey AS, West Germany, from July 1962 to August 1965, and then as Plans Officer for the 834th Air Division at England AFB, Louisiana, from August 1965 to July 1966. He then served as Director of Command and Control with Headquarters 9th Air Force at Shaw AFB, South Carolina, from July 1966 to April 1969, followed by service as Chief of the Emergency Actions Element with the 314th Air Division at Osan AB, South Korea, from April 1969 to June 1970. Col Keen's final assignment was back at Headquarters 9th Air Force at Shaw AFB, where he served as Assistant Chief of the Current Operations Division, and Director of Command and Control from June 1970 until his retirement from the Air Force on December 31, 1972. Robert Keen died on May 29, 1992.

His Distinguished Service Cross Citation reads:

For extraordinary heroism in action against the enemy, 13 May 1944. On this date Lieutenant Keen alone with his flight of fighter aircraft, unmindful of the overwhelming odds, courageously attacked 30 FW 190's, which were positioning for a pass at a box of B-17 bombers, and immediately destroyed one. So closely did he press his attack that no sooner had he set his sights on another enemy and fired than the German bailed out. Lieutenant Keen now found himself separated from his flight, yet despite the fact that he was alone, deep in enemy territory and surrounded by hostile planes he disregarded his personal safety and engaged and destroyed two more FW 190's. So great was his will to destroy the enemy that he refused to disengage from the enemy until his final rounds of ammunition were expended. The skill, aggressiveness and heroism displayed by Lieutenant Keen on this occasion reflect great credit upon himself and the Armed Forces of the United States.