Several soldiers in the film were played by actual soldiers from Combat Outpost Keating.

Clinton Romesha has been critical of the choice of the actual Outpost Keating base in the Nurestan Province in Afghanistan where he served, describing it as "like being in a fishbowl or fighting from the bottom of a paper cup".

Scott Eastwood (Clint Eastwood), Milo Gibson (Mel Gibson), and James Jagger (Mick Jagger) are all sons of famous directors/actors/musicians. Will Attenborough is the grandson of famed director/actor Richard Attenborough, and Scott Alda Coffey is the grandson of actor Alan Alda.

Considerable dramatic license was taken to time-compress the events depicted in the film. Benjamin Keating was posthumously promoted from First Lieutenant to Captain. He was the Executive Officer (second-in-command) of A Troop, 3rd Squadron 71st Cavalry but was never the Troop Commander. He was killed on 26 November 2006 in a truck accident as depicted in the film; he never worked with Clinton Romesha, Ty Carter or any other members of B Troop, 3rd Squadron 61st Cavalry who did not arrive until May 2009 to garrison what was by then already renamed Outpost Keating, two and a half years after his death.

Scott Eastwood never met Clinton Romesha, the Staff Sergeant he portrays, though he did manage to discuss at length his role over a phone conversation.