Hilliard was born on the 26th of July, 1933, in Cornelia, Georgia, and shortly before turning eighteen, he joined the US Air Force, becoming an air policeman with the Strategic Air Command. He was soon accepted into the aviation cadet program and was commissioned as an officer in June of 1955. Before qualifying to be a fighter pilot, Hilliard served as an instructor and he was then a forward air controller when he deployed to the Republic of Vietnam in April of 1966 with the 21st Tactical Air Support Squadron. In under a year, he had flown 487 combat missions and earned the Distinguished Flying Cross, as well as seventeen Air Medals, which are typically awarded for single acts of merit or gallantry in combat or for meritorious service in a combat zone. His final mission would be where his actions would earn him the Medal of Honor. The citation reads:

For conspicuous gallantry and intrepidity in action at the risk of his life above and beyond the call of duty. As a forward air controller Capt. Wilbanks was pilot of an unarmed, light aircraft flying visual reconnaissance ahead of a South Vietnam Army Ranger Battalion. His intensive search revealed a well-concealed and numerically superior hostile force poised to ambush the advancing rangers. The Viet Cong, realizing that Capt. Wilbanks' discovery had compromised their position and ability to launch a surprise attack, immediately fired on the small aircraft with all available firepower. The enemy then began advancing against the exposed forward elements of the ranger force which were pinned down by devastating fire. Capt. Wilbanks recognized that close support aircraft could not arrive in time to enable the rangers to withstand the advancing enemy, onslaught. With full knowledge of the limitations of his unarmed, unarmored, light reconnaissance aircraft, and the great danger imposed by the enemy's vast firepower, he unhesitatingly assumed a covering, close support role. Flying through a hail of withering fire at treetop level, Capt. Wilbanks passed directly over the advancing enemy and inflicted many casualties by firing his rifle out of the side window of his aircraft. Despite increasingly intense antiaircraft fire, Capt. Wilbanks continued to completely disregard his own safety and made repeated low passes over the enemy to divert their fire away from the rangers. His daring tactics successfully interrupted the enemy advance, allowing the rangers to withdraw to safety from their perilous position. During his final courageous attack to protect the withdrawing forces, Capt. Wilbanks was mortally wounded and his bullet-riddled aircraft crashed between the opposing forces. Capt. Wilbanks' magnificent action saved numerous friendly personnel from certain injury or death. His unparalleled concern for his fellow man and his extraordinary heroism were in the highest traditions of the military service, and have reflected great credit upon himself and the U.S. Air Force.

Hilliard was pulled from his wreckage by one of the Rangers he was trying to help and was loaded onto a helicopter for evacuation, where he died at the age of 33. Almost one year later, his wife, Rosemary, received his Medal of Honor from the Secretary of the Air Force, Harold Brown, in a ceremony at the Pentagon on the 24th of January, 1968.

In Clarkesville, Georgia, the Hilliard A Wilbanks Middle School was named in his honor, as well as dedication of a six foot tall granite memorial in Cornelia, Georgia. As well as being inducted into the Georgia Aviation Hall of Fame, in 2011, the Hilliard A Wilbanks Foundation was established in order to promote the values of Courage, Sacrifice, and Patriotism, and awards scholarships to Georgia high school seniors. Two of Hilliard's family serve as directors for the foundation: Patricia, his sister, is the current secretary with her husband being the president, and John, his youngest son, is also on the board. He and Rosemary had four children: Tommy, Paula, John, and Debbie. Hilliard Almond Wilbanks is one of nineteen Medal of Honor recipients from the Air Force and is buried in the Fayette Cemetery in Fayette, Mississippi. His name appears on Panel 15E, Line 88 of the Vietnam Veterans Memorial Wall in Washington DC.