Direct proof of use
The AGM-114 Hellfire missile family was used by U.S. Army AH-64 Apache helicopters during the 1990 Gulf War. A U.S. Army Redstone Arsenal history states that eight Apaches from the 101st Airborne Division crossed into Iraq before dawn on January 17, 1991 and launched laser-guided Hellfire missiles against two Iraqi early-warning ground-control radar sites.
The same Army account describes the Apaches firing Hellfire missiles and 2.75-inch Hydra-70 rockets at 02:38, destroying the radar sites within four minutes and opening a corridor for the first coalition air strikes into Iraq. Redstone's Hellfire system history separately identifies the engagement as the first shots of Operation Desert Storm.
Sources: Redstone Desert Storm Role, Redstone Hellfire System History
Task Force Normandy
Army University Press identifies the January 17 mission as Task Force Normandy, a joint Army-Air Force operation built around eight Army AH-64 Apache helicopters and four Air Force MH-53J Pave Low helicopters. Its purpose was to destroy two Iraqi early-warning radar sites and open an air corridor at the beginning of the air campaign.
Army University Press records that the Apaches were recommended for the mission with Hellfire missiles, Hydra-70 rockets, and 30 mm guns because the attack helicopters could destroy hard and soft targets. Air & Space Forces Magazine's contemporary account likewise describes the Apache crews releasing laser-guided Hellfire missiles against the Iraqi radar sites in the predawn hours of January 17, 1991.
Sources: Army University Press Task Force Normandy, Air & Space Forces Apache Attack
Broader Gulf War role
Hellfire use in the war was not limited to the opening radar raid. Redstone's Desert Storm history says the anti-armor missile systems sent to Southwest Asia included Dragon, Hellfire, Shillelagh, and TOW, and that only Shillelagh was not used in combat during Operation Desert Storm.
Redstone further estimates that between 2,900 and 4,000 Hellfire missiles were fired during Operation Desert Storm, with 80 to 90 percent judged to have hit their targets. The same source lists target types that included tanks, other armored vehicles, radar sites, bunkers, and fortified positions, while noting that Hellfire's long range also contributed to several friendly-fire incidents.
Sources: Redstone Desert Storm Role