Doc Bahnsen was born on November 8, 1934, in Albany, Georgia. He entered the U.S. Military Academy at West Point, New York, on July 1, 1952, and was commissioned a 2d Lt of Infantry on June 5, 1956. Lt Bahnsen attended the Infantry Officer Basic Course at Fort Benning, Georgia, from August to September 1956, and then Jump School at Fort Benning in January and February 1957. He next completed Fixed Wing Aviator flight training at Fort Rucker, Alabama, in September 1957. He served as an aviator in the Artillery Flight with the 3d Aviation Company of the 3d Infantry Division at Fort Benning from September 1957 to April 1959, followed by service as a Platoon Leader and Company Commander in the 1st Medium Tank Battalion of the 68th Armor Regiment at Kitzigen, West Germany, from May 1959 to May 1961. Capt Bahnsen next attended Rotary Wing Aviator flight training at Camp Wolters, Texas, from May to September 1961, and then the Armor Officer Career Course at Fort Knox, Kentucky, from September 1961 to July 1962. He served as an Armored Cavalry Instructor at Fort Knox from July 1962 to August 1964, and he then attended U.S. Army Command and General Staff College at Fort Leavenworth, Kansas, from August 1964 to August 1965. His next assignment was as a UH-1 Iroquois pilot with the 118th Aviation Company of the 145th Combat Aviation Battalion in South Vietnam from October 1965 to May 1966, followed by service as Assistant S-3 for the 12th Aviation Group in South Vietnam from May to August 1966. Maj Bahnsen served as a staff officer in the Army Aviation Directorate with the Office of the Assistant Chief of Staff for Force Development in the Pentagon from December 1966 to August 1968, and he then attended AH-1 Cobra gunship training at Hunter Army Airfield, Georgia, from August to September 1968. His next assignment was as Commander of the Air Cavalry Troop and then 1st Squadron with the 11th Armored Cavalry Regiment in South Vietnam from September 1968 to September 1969, followed by service as the Battalion Commander of 1st Battalion, 32d Armor Regiment of the 3rd Armored Division at Friedberg, West Germany, from November 1969 to July 1971. LTC Bahnsen attended Army War College at Carlisle Barracks, Pennsylvania, from August 1971 to August 1972, and then served as the Armor Team Leader with the Combat Arms Training Board at Fort Benning from August 1972 to April 1974. His next assignment was with the Tank Training Task Force at Fort Knox from May 1974 to January 1975, followed by service with Army Training and Doctrine Command (TRADOC) at Fort Monroe, Virginia, from January 1975 to June 1977. COL Bahnsen served as TRADOC Systems Manager for Attack Helicopters at Fort Rucker from June 1977 to August 1978, and then as Commander of the 1st Aviation Brigade at Fort Rucker from August 1978 to May 1980. BG Bahnsen's next assignment was as Assistant Division Commander for the 2d Armored Division at Fort Hood, Texas, from June 1980 to July 1982, followed by service as Chief of Staff of the Combined Field Army (Republic of Korea/United States) in South Korea from August 1982 to September 1984. His final assignment was as Chief of Staff for III Armored Corps at Fort Hood from September 1984 until his retirement from the Army on July 1, 1986. He was inducted into the Army Aviation Hall of Fame in 2007.

His Distinguished Service Cross Citation reads:

For extraordinary heroism in connection with military operations involving conflict with an armed hostile force in the Republic of Vietnam. Major Bahnsen distinguished himself by exceptionally valorous actions on 23 January 1969 as Commanding Officer, Air Cavalry Troop, 11th Armored Cavalry Regiment. Informed of a sizable enemy force, Major Bahnsen landed at the hostile area, reconnoitered and marked a landing zone for a rifle platoon in full view of the hostile troops. Leaving the site, he saw fifteen communists and engaged them with his rifle, firing from the window of his helicopter. He killed two of the enemy and remained at a low altitude to direct additional fire upon them until his crew chief was seriously wounded by the hostile barrage which struck their ship. Major Bahnsen evacuated the crew chief, refueled and rearmed, and sped back to the battle. Again taking the communists under fire and forcing them to a confined area, he marked their position and directed five air strikes against them, while at the same time controlling four separate rifle platoons. Intense enemy fire crippled his ship, forcing him to acquire another aircraft. On his return, Major Bahnsen landed to guide in the lift ships carrying an additional infantry unit, and then led a rifle platoon through dense terrain to personally capture two enemy who were attempting to escape, While the captives were evacuated by helicopter, he remained on the ground and led the squad two kilometers back to friendly positions. Major Bahnsen's extraordinary heroism and devotion to duty were in keeping with the highest traditions of the military service and reflect great credit upon himself, his unit, and the United States Army.