In an interview he gave during the 2018 Toronto International Film Festival, Robert Redford talked about this comedic film being a good note to end on, since the actor wanted his "last acting job to be fun."
Although he receives fourth billing, Keith Carradine's role was almost completely dropped; he appears for literally three or four seconds with a single line of dialogue. (Director David Lowery has stated the cut footage will be included on the DVD.)
There are several "Easter egg" references to Robert Redford's earlier films, including the opening legend, which is nearly identical to the one that opens "Butch Cassidy and the Sundance Kid" ("Not that it matters, but most of what follows is true") and the scene between Redford and Casey Affleck, where Affleck runs a finger over the side of his nose, which was the signal in "The Sting" between the con men that they were fellow-travelers.
David Lowery tried to write the true crime version of this movie and the journalistic version of what really happened, and Robert Redford never felt like he fit into that. In other words, according to Lowery himself, his idea of who Robert Redford was as an actor never really fit into the true story of Forrest Tucker. So after many, many drafts, he realized that what he needed to write was the movie that Forrest Tucker would have wanted to see. He needed to write the version of Forrest Tucker that he saw in his own head as opposed to the one that really showed all the things he did. There was a thin line between two, but it was a very important line and that line allowed him to write a movie that was the version that Robert Redford could excel playing.
The other members of the Over-The-Hill Gang were John Waller (played by Tom Waits), who'd escaped maximum-security San Quentin with Tucker in 1979; another man with whom they'd built a boat from smuggled supplies and nearly made it past the guard tower before high waves capsized them; a guard who saw their hand-painted outfits and overturned kayak was won over by a joke Tucker made, and let them go on their way; and Teddy Green (played by Danny Glover), an escape artist and fellow bank robber Tucker met during his 1950s stint in Alcatraz.
In the hospital scene, John Hunt (Casey Affleck) as he leaves the room of Forrest Tucker (Robert Redford) swipes the side of his nose with his left index finger. The same gesture occurs several times in Robert Redford's "The Sting" by Redford's, Paul Newman's, Harold Gould's characters, and others as an nonverbal acknowledgment that "I see you and I'm here and ready for the sting."
At a certain point while he was writing the script, David Lowery decided that he has no business telling (A) a true story, (B) a story about cops and robbers, and (C) a story about people who have lived a great deal of life.
When she is dropped off at her home by Robert Redford's character Forrest, Sissy Spacek's face is momentarily illuminated by a bright red light, supposedly the brake light of Forrest's car as he turns the ignition. This image is a clear reference to the climax of Spacek's earlier film Carrie.
The Old Man & the Gun was the first time that Sissy Spacek and Robert Redford had worked together. However they both did movies with Michael Ritchie: Redford did Downhill Racer (1969) and The Candidate (1972) and Spacek did Prime Cut (1972).
Near the end, Tucker hijacks a car with a young mother and her son but only until he realizes her son is in the car. He gets them to stop at a diner, where he leaves them and takes their car. Above them is a sign about the good prices of the meal, saying "It's a steal!"
When Forrest Tucker settled into a happy life with third wife Jewell Centers in 1993, she -unlike her movie counterpart (played by Sissy Spacek)- had no idea of her husband's criminal career until his 80s arrest in 1999, thinking he was a stock broker named Bob Callahan.
The shot of Robert Redford on the horse with a line of cop cars speeding in the distance was David Lowery's idea. For at a certain point while writing the chase scene, Lowery felt like he needed to take this pursuit further, leave reality behind, enter the symbolic realm and once again let Robert Redford status as a legend take precedence in the sequence. Also according to Lowery, it was one of those rare moments on set where you just feel like you're watching a little bit of history happen in front of you.
According to David Lowery, the final montage of Forrest Tucker is like a summary of Robert Redford's career. It is as if "all those escapes almost feel like it's like you're listing the movies he's made".
It was a suggestion on Tom Waits' part that perhaps his character could have a monologue. When Waits brought the idea to the table, David Lowery asked him if he had any stories in mind that he'd like to tell and he told Lowery the Christmas story. Which as far as Lowery is concerned, is completely 100% true.