Harry Ettmueller was born on November 10, 1944, in Pleasantville, New Jersey. He enlisted in the U.S. Army on January 7, 1963, and was trained as an Artillery Plotter, where he served with the 35th and 17th Artillery Brigades at Fort Meade, Maryland, from March 1963 to May 1964. Ettmueller next went through Crypto Repair and Television Repair School at Fort Monmouth, New Jersey, from May 1964 to July 1965. He then served as a Television Broadcast Engineer, serving in South Korea with AFKN from July 1965 to June 1966, and then with the U.S. Military Assistance Command in South Vietnam with AFVN from June to November 1966. Sgt Ettmueller then returned to South Korea, where he served from November 1966 to March 1967, and then returned to the U.S. Military Assistance Command in South Vietnam assigned to the 1st Signal Brigade and then AFVN Headquarters. On February 5, 1968, Sgt Ettmueller was captured in the city of Hue when the city came under attack by Viet Cong and North Vietnamese military forces, and was later moved to the North Vietnamese prison system. After spending 1,857 days in captivity, he was released during Operation Homecoming on March 5, 1973. Ettmueller was briefly hospitalized to recover from his injuries and then trained as an Army Clinical Specialist. He served with the 41st Combat Support Hospital at Fort Sam Houston, Texas, from November 1975 to June 1976, and then as an instructor with Company B, 3rd Battalion at the Academy of Health Sciences, also at Fort Sam Houston, from June 1976 until he left active duty on July 5, 1977. On April 8, 2007, he was inducted into the United States Army Public Affairs Hall of Fame. Harry Ettmueller died on March 14, 2020.

His Silver Star Citation reads:

Staff Sergeant Harry L. Ettmueller distinguished himself by gallantry and intrepidity in connection with military operations against an opposing armed force while serving with Detachment Number 5, American Forces Television Station, Hue, Republic of Vietnam, on 2 February 1968 during the Communist "Tet Offensive." At approximately 1900 hours a much superior numerical force of North Vietnamese Regulars attempted a sneak attack on the quarters of Detachment Number 5 personnel located at Number 6 Tran Duc Street, Hue. Although suffering from wounds received in the right thigh by an enemy fragmentation grenade on 1 February 1968, then Specialist Five Harry L. Ettmueller, with total disregard for his personal safety and previously incurred wound, took a position outside the entrance to the rear of the building and deterred an enemy attempt to enter the building. His immediate actions during the enemy's initial assault and during the 16-hour battle that followed was instrumental in deterring the enemy's attempt to overrun Detachment's Number 5 position and thereby contributed to the saving of the lives of the detachment members. His position was later overrun and he was held as a Prisoner of War until his release on 5 March 1973. Staff Sergeant Ettmueller's heroic actions are in keeping with the highest tradition of the services and reflect great credit on himself and the United States Army.