- "Look, you wanted to believe that the Army had straightened me out. Look, I'm your brother, but I'm not built like you. I didn't take to the military like you did. You saw the world as something to be fixed. I only saw it as broken, so I made sure I had enough to survive in it."
- —Andy Diggle to John Diggle[src]
The United States Army is the army of the United States of America.
In the 2000s, John Diggle served in the Army, and completed three tours of duty during the War on Terrorism. In 2005, while a Sergeant, he convinced his brother Andy to enlist. By 2010, both John and Andy had mustered out as a Master Sergeant and Sergeant, respectively.
In 2010, the Alpha-Omega super-virus eventually got the attention of the United States Army. After a debrief with Oliver Queen, the Alpha-Omega bio weapons problem became a United States Army operation. General Matthew Shrieve removed Amanda Waller's authority as the leader of A.R.G.U.S. for conducting an unauthorized operation without authorization from the United States government, and for committing unspeakable acts.
In 2014, Major General Wade Eiling began investigating metahumans, attempting to recruit or blackmail them into working for the US military as weapons as well as experiment on them in order to give their powers to other soldiers, which made him an enemy to Team Flash. Years before, Eiling worked with Dr. Harrison Wells/Eobard Thawne at S.T.A.R. Labs on other experiments intending to create super-soldiers.
- General Matthew Shrieve (deceased)
- Lieutenant General Ulysses S. Grant, Union Army (Ret.)
- Lieutenant General J.G. Walker (incarcerated; theft of a weapon of mass destruction, the murder of an enlisted soldier and try to frame John Diggle for his crimes)
- Colonel Ted Gaynor (deceased)
- Lieutenant Joyner (incarcerated)
- First Sergeant Floyd Lawton (retired)
- Master Sergeant John Diggle (inactive; arrested for war crimes, but later proved innocent)
- Sergeant First Class Rock (deceased)
- Sergeant Andy Diggle (deceased)
- Sergeant Bette Sans Souci (deceased)
- Private First Class James Jackson (deceased)
- Lyla Michaels (reassigned to A.R.G.U.S.)
- Ezra Barnes (incarcerated)
- Shadowspire Special Forces Unit (gone rogue)
- Baron Reiter (deceased)
- Conklin (deceased)
DC's Legends of Tomorrow
- "Crisis on Earth-X, Part 1" (mentioned)