William Barber was born on November 20, 1919, in Dehart, Kentucky. He enlisted in the U.S. Marine Corps on March 14, 1940, and after completing basic training and parachutist school, he served as an instructor in the Parachute Training School at San Diego, California, and at Camp Lejeune, North Carolina, from March 1942 until he entered Officer Candidate School at MCS Quantico, Virginia, in June 1943. He was commissioned a 2d Lt in the Marine Corps on August 11, 1943, and then attended the Reserve Officers Class at Quantico from August to October 1943. After additional training, Lt Barber served with E Company, 2nd Battalion, 26th Marine Regiment, 5th Marine Division at Camp Pendleton, California, from January 1944 to January 1945, and then deployed to the Pacific Theater from January 1945 to October 1945, where he participated in the Battle of Iwo Jima in February and March 1945. After returning to the U.S., Capt Barber served with the 5th Engineering Battalion of the 5th Marine Division in San Diego, California, until transferring to the 2nd Engineering Battalion of the 2nd Marine Division in late November 1945, serving there until January 1946. His next assignment was as a training officer at MCRD San Diego from March to April 1946, followed by service as a recruiting officer in Milwaukee, Wisconsin, from April to November 1946. He served as Commanding Officer of B Company, 1st Battalion, 8th Marine Regiment, 2nd Marine Division, at Camp Lejeune from November 1946 to September 1947, and then served as an instructor with the U.S. Marine Corps Reserve in Altoona, Pennsylvania, from September 1947 to September 1949. Capt Barber next served at Naval Base Philadelphia, Pennsylvania, from September 1949 to October 1950, and then served with 2nd Battalion, 7th Marine Regiment, 1st Marine Division in Korea from October 1950 until he was evacuated for his injuries during the Battle of Chosin Reservoir in December 1950. He was hospitalized in Japan until returning to the U.S. in March 1951, and then served with the 1st Recruit Training Battalion at MCRD San Diego from April 1951 to August 1953. Maj Barber next attended the Advanced Infantry Course at Fort Benning, Georgia, from August 1953 to March 1954, followed by service with 2nd Battalion, 2nd Marine Division at Camp Lejeune from April 1954 to January 1956. After completing Strategic Intelligence School, he served as Assistant Naval Attache and Assistant Naval Attache for Air in Bangkok, Thailand, from March 1956 to August 1958, and then served as an instructor at the Marine Corps Schools at Quantico from October 1958 to June 1962. Col Barber next served as Commander of 3rd Recon Battalion, 3rd Marine Division on Okinawa from July 1962 to April 1963, and then as Executive Officer of the 9th Marine Regiment, 3rd Marine Division from April to July 1963. He then received an assignment to complete his Bachelor's degree from September 1963 to May 1964, followed by service at Headquarters U.S. Marine Corps in the Pentagon from June 1964 to July 1967. Col Barber's next assignment was on the staff of the 2nd Marine Division from July 1967 to February 1968, and then as Commanding Officer of the 2nd Marine Regiment, 2nd Marine Division at Camp Lejeune from February 1968 to May 1969. His final assignment was as Psychological Operations Officer for III Marine Amphibious Force in South Vietnam from June 1969 to March 1970. Col Barber retired from the Marine Corps on May 1, 1970. He died on April 19, 2002, and was buried at Arlington National Cemetery.

His Medal of Honor Citation reads:

For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty as commanding officer of Company F in action against enemy aggressor forces. Assigned to defend a 3-mile mountain pass along the division's main supply line and commanding the only route of approach in the march from Yudam-ni to Hagaru-ri, Capt. Barber took position with his battle-weary troops and, before nightfall, had dug in and set up a defense along the frozen, snow-covered hillside. When a force of estimated regimental strength savagely attacked during the night, inflicting heavy casualties and finally surrounding his position following a bitterly fought 7-hour conflict, Capt. Barber, after repulsing the enemy gave assurance that he could hold if supplied by airdrops and requested permission to stand fast when orders were received by radio to fight his way back to a relieving force after 2 reinforcing units had been driven back under fierce resistance in their attempts to reach the isolated troops. Aware that leaving the position would sever contact with the 8,000 marines trapped at Yudam-ni and jeopardize their chances of joining the 3,000 more awaiting their arrival in Hagaru-ri for the continued drive to the sea, he chose to risk loss of his command rather than sacrifice more men if the enemy seized control and forced a renewed battle to regain the position, or abandon his many wounded who were unable to walk. Although severely wounded in the leg in the early morning of the 29th, Capt. Barber continued to maintain personal control, often moving up and down the lines on a stretcher to direct the defense and consistently encouraging and inspiring his men to supreme efforts despite the staggering opposition. Waging desperate battle throughout 5 days and 6 nights of repeated onslaughts launched by the fanatical aggressors, he and his heroic command accounted for approximately 1,000 enemy dead in this epic stand in bitter subzero weather, and when the company was relieved only 82 of his original 220 men were able to walk away from the position so valiantly defended against insuperable odds. His profound faith and courage, great personal valor, and unwavering fortitude were decisive factors in the successful withdrawal of the division from the deathtrap in the Chosin Reservoir sector and reflect the highest credit upon Capt. Barber, his intrepid officers and men, and the U.S. Naval Service.