(Capcom's primary storyline)
The United States Army is the primary ground force in the U.S. Military, primarily handling external operations with the Army National Guard handling internal matters.
During the Cold War, the US Army was one of a number of interested clients for the Umbrella Corporation's bioweapons program. It was also involved in secret bioweapons research which, though illegal in the 1972 Bioweapons Convention, continued into the 1990s. In 1998, their bioweapons project received a potential gain with Golgotha, a virus engineered by Umbrella USA virologist Dr. William Birkin. Moles within the US military became aware of this plan, and Birkin was shot in a raid by Umbrella's USS paramilitary group before he could defect.
In the aftermath of the Birkin attack, an experimental Epsilon strain of t-Virus contaminated Raccoon City's drinking water, mutating tens of thousands within days. The Pentagon was quickly made aware, and drew up plans for a major operation which they formally announced in the early hours of 24 September. By the following day, the city was successfully blockaded, with checkpoints positioned on the highways to control the flow of traffic. The Army National Guard soon arrived to assist the Regular Army. Civilians were evacuated out from the city and taken to designated zones for testing to confirm they were not infected. The initial evacuations suffered setbacks, with the loss of a Chinook that was carrying dozens of civilians. The Army nonetheless continued its operations within the city itself, setting up bases around the city, including the highway overpass. Along with wagons transporting squads, armoured vehicles also found their use in tackling the disorder. The blockade managed to fail in some places, allowing unaware citizens to enter the city.
Alongside the Army's official mission were secret missions assigned to Delta Force to salvage its interest in Umbrella's bioweapons, which included the raid on the Raccoon General Hospital where data on the t-virus was kept. Umbrella's private subway was infiltrated with the goal of recovering a Golgotha sample from NEST, though the unit was misled to the far-away Incineration Disposal Plant P-12A, where it was wiped-out in combat with five T-103 Tyrants sent to kill them after Umbrella's moles reported in their location. Ultimately, Raccoon City was wiped out in a missile strike following the Army's virtual abandonment of its missions there, having given up the city as a lost cause.
In the years following the disaster and the Army's ineffectual response, the US military sought out a trained anti-bioweapon force, which became the Federal Bioterrorism Commission. This was, however, disbanded with its assets transferred to the UN-sanctioned BSAA. Responsibilities for anti-bioweapon missions within the United States then fell onto the 75th Ranger Regiment which, in 2005, was entrusted with the extermination of Zombies in Harvardville following a bioterror incident and arresting the terrorist behind it.
In 2011, the US Army cooperated with Russian forces in occupying and disarming the Eastern Slav Republic when it was discovered that the national government had been employing B.O.Ws during the country's civil war.
- Three playable characters in the Resident Evil series have served in the US Army. Jill Valentine served for some undisclosed years and trained with Delta Force. Mark Wilkins served during the Vietnam War. The biographies for the original Resident Evil indicated that Albert Wesker, between 1991 and 1996, was a commissioned engineering officer in the United States Army while simultaneously being assigned to Umbrella's Intelligence Division.
- It's possible the MPs escorting Billy to his execution are members of the Army, since they carry what is known as the Army Handgun (though it is never explained exactly how Billy obtained this weapon, this is the most logical assumption).
- Billy's handgun is called the "Army Handgun" and is a modified Colt M1911. Examining the weapon explains that it is the standard handgun of the U.S. Army, which is inaccurate. While the U.S. Marine Corps still uses the Colt, the Army has switched to the Beretta 92FS (the weapon the Samurai Edge is built around). Likely this is either a translation error, or an attempt by Capcom to differentiate between both character's handguns.
- Resident Evil Archives. BradyGames. p. 293.
- Resident Evil Outbreak (2003), scene: ""Outbreak" KEVIN: ENDING".
- Famitsu interview with Yasuhisa Kawamura.
- Resident Evil Outbreak File #2 (2004), scene: "No Hope (Kevin)".
- Resident Evil Outbreak File #2 (2004), level: "End of the Road".
- Resident Evil Outbreak (2003), level: "Decisions, Decisions".
- Resident Evil: The Umbrella Chronicles (2007), file: "Emergency Orders".
- Resident Evil: Degeneration (2008).