Someone rhetorically mentions Atticus Finch, a reference to To Kill a Mockingbird (1962), which was Robert Duvall's screen debut, playing Arthur "Boo" Radley.
Joseph Palmer says in the film that he is seventy-two years old. Robert Duvall was eleven years older when the film was released, and became the oldest Oscar nominee ever for his performance at the age of eighty-four.
First feature release from "Team Downey", Robert Downey, Jr. and wife Susan Downey's production company.
Jeremy Strong prepared for his role by spending time with an autistic person, carefully observing their behavior. He had stayed in character throughout filming and would show up on set on days where he was not needed.
The screenplay for this film was featured in the 2012 Blacklist; a list of the "most liked" unmade scripts of the year.