Some guest actors have said that the working environment on the show was very different from other shows, because the writers were really open to suggestions from the cast, even while shooting scenes, to the point of stopping shooting for a while and sitting around to discuss the scene if there was room for improvement.
Walton Goggins, who was born in Alabama and grew up in Georgia, originally declined the role of Boyd Crowder out of concern that the character would portray a negative stereotype of Southerners. He changed his mind and did the pilot as a favor to Timothy Olyphant, whom he knew through friends. It was supposed to be one episode only; Boyd originally died at the end of the pilot, as he did in the novel the show was based on. However, when the character scored well with test audiences, it was decided to reshoot the ending of the pilot to allow Boyd to return as a recurring character.
The character of Theo Tonin was supposed to be back for season four, but Adam Arkin was too busy directing episodes of The Americans (2013), so the writers had to create his subordinate Nicky Augustine. Between 2010-15, Arkin also directed ten episodes of this series.
The character Raylan Givens was created by novelist Elmore Leonard, and has appeared in two of his novels, "Pronto" (filmed as Pronto (1997)) and "Riding the Rap". Givens also appeared in Leonard's short story "Fire in the Hole", which was the basis of the pilot episode of this series.
Throughout the series, the characters frequently drank Kentucky bourbon, particularly the top-shelf brand Blanton's. The props department poured the liquor out of the bottles, and replaced it with watered-down Diet Coke for the actors to drink instead. Timothy Olyphant took the real bourbon home in mason jars. On the night the series finale aired, he brought a jar of bourbon on Conan (2010) to toast to the show with Conan O'Brien.
Timothy Olyphant, who plays Marshal Raylan Givens, also starred in the HBO series Deadwood (2004) as Sheriff Seth Bullock. Several other actors who appeared in "Deadwood" make guest appearances in this series: W. Earl Brown, who played "Dan Dority" in "Deadwood", plays a prisoner who takes two officers hostage in the Marshal's office; Sean Bridgers ("Johnny Burns") as a would-be assassin of a judge; Peter Jason ("Con Stapleton") plays an art collector; Ray McKinnon (Rev. Smith) plays an assassin sent from Miami to kill Raylan; Brent Sexton ("Harry Manning") plays a sheriff who helps Givens; Pruitt Taylor Vince ("Mose Manuel") plays a pawn shop owner with ties to the Dixie Mafia; Jim Beaver ("Ellsworth") plays Shelby, a mining operation manager, who then becomes Boyd Crowder's man for sheriff; Stephen Tobolowsky ("Hugo Jarry") plays Special Agent Barkley, an FBI agent who has an adversarial relationship with Raylan; Gerald McRaney ("George Hearst") plays Josiah, a former cohort of Arlo Givens on house arrest; Garret Dillahunt ("Francis Wolcott" / "Jack McCall") plays Ty Walker, one of Avery Markham's henchmen.
When Raylan Givens (Timothy Olyphant meets Josiah Cairn (Gerald McRaney), the dialogue between them is almost verbatim to that of their roles in Deadwood (2004) as Seth Bullock (Olyphant) and George Hearst (McRaney): "Oh, come on, man. I haven't forgotten you." "Made an impression, did I?" "You could say that. That bullshit you tried pulling after the mine explosion in '85. Taking money from the widows to try to prove it was the mine's fault, then taking money from the mine to try to cover it up."
The show was based on Elmore Leonard's novella "Fire in the Hole," which introduced Raylan Givens, but another studio had the rights to his book "Pronto," also featuring Raylan, which was made into a TV movie, Pronto (1997) had been made into a TV movie. The writers were unable to use any stories from "Pronto" without altering the characters and plot significantly.
Mykelti Williamson (Limehouse) uses a machete-type knife to cut off Quarles' arm. In Species II (1998) Williamson's character, Gamble, picks up a machete and says he was "going back to Africa on somebody's ass", namely the alien he and Michael Madsen are going after.
The trivia item below may give away important plot points.
The fedora Raylan takes from Boon after killing him in the final episode more closely resembles the one described in the short story that spawned the series than the Stetson hat Raylan wore throughout the series.