Justified was originally titled Lawman before FX ordered a 13-episode first season on July 28, 2009.

The series was developed by Graham Yost based on Elmore Leonard's short story 'Fire in the Hole' featuring the character Raylan Givens; the pilot episode was referred to as the 'Fire in the Hole pilot' during production and kept that title.

Boyd Crowder, played by Walton Goggins, was originally intended to die in the pilot episode, but showrunner Graham Yost kept the character alive after test audiences responded well to Goggins' performance, promoting him to the main cast from season 2 onward.

The character Rachel Brooks, played by Erica Tazel, was later included by Elmore Leonard himself in his final novel, Raylan.

While the pilot was filmed in Pittsburgh and the suburbs of Kittanning and Washington, Pennsylvania, all subsequent episodes were shot in California, with the small town of Green Valley, California standing in for Harlan, Kentucky.

In the pilot, Pittsburgh's David L. Lawrence Convention Center was used to represent a small-town airport, while the construction site of the new Consol Energy Center served as the 'new courthouse'.

Starting with season three, the production switched to shooting with Red Digital Cinema's EPIC camera; director of photography Francis Kenny said the switch made the show 'look better than ever' and turned the producers into 'true believers of the Red System'.

The show's theme song, 'Long Hard Times to Come,' was performed by Gangstagrass featuring rapper T.O.N.E-z, and was nominated for a 2010 Emmy Award for Outstanding Original Main Title Theme Music.

Elmore Leonard ranked Justified as one of the best adaptations of his work—alongside Get Shorty, Jackie Brown, 3:10 to Yuma, and Out of Sight—and praised Timothy Olyphant's casting as Raylan, saying he was 'the kind of guy I saw when I wrote his lines'.

The decision to end the series after six seasons rather than continue for a seventh was driven primarily by lead actor Timothy Olyphant and developer Graham Yost, despite financial incentives to keep the show going, according to FX president John Landgraf.

A limited sequel series, Justified: City Primeval, based on Elmore Leonard's novel City Primeval, premiered in 2023 with Timothy Olyphant reprising his role as Raylan Givens; it also features Olyphant's real-life daughter, Vivian Olyphant, in the cast.