The episode was written by series developer Graham Yost and executive producers Fred Golan, Dave Andron and Benjamin Cavell and directed by Adam Arkin.
The series is based on Elmore Leonard's stories about the character Raylan Givens, particularly "Fire in the Hole", which serves as the basis for the episode.
The series revolves around the inhabitants and culture in the Appalachian Mountains area of eastern Kentucky, specifically Harlan County where many of the main characters grew up.
The season also introduced main antagonist Avery Markham, a big-time criminal recently back from Colorado with a small fortune from legalized cannabis, intending to take over Harlan for his business.
The finale received universal acclaim from critics and audiences, who praised the directing, writing, performances, tension, pace, cinematography and closure, with many declaring it brought the series "full circle".
At the barn, Ava (Joelle Carter) is brought before Avery (Sam Elliott), who is unhappy to see she only carried $1 million in the bag and demands to know the location of the rest of the money.
As authorities search for Ava, Tim (Jacob Pitts) and Rachel (Erica Tazel) are notified that they found a gator-tooth necklace in the ground (not knowing it belonged to Dewey Crowe).
Avery gets mad when he finds that Zachariah didn't show up at the location when suddenly, Boyd arrives holding his officer at gunpoint.
4 years later, Raylan lives in Miami, working for the local Marshal's office and often spends time with his daughter Willa while Winona (Natalie Zea) is now married to a man named Richard (Jason Gedrick).
Raylan deduces that with Ellen May (Abby Miller) and Limehouse (Mykelti Williamson) unavailable, Duffy (Jere Burns) helped her get out of Harlan in exchange for Avery's $9 million, after which he disappeared.
In January 2014, FX Original Programming President, Nick Grad mentioned that the series would probably end with the sixth season, "We like having shows that rate really well, and there’s an instinct that you want it to go on forever.
[11] Many considered that the title referred to the promise made in the first episode, where Raylan says "you make me pull, I'll put you down" to Boyd while talking on the church.
"[12] The central idea of the episode was growth, with Yost explaining, "Tim [Olyphant] and I talked right from the beginning of the series that Raylan could grow, but not by much.
[18] The line "We dug coal together" was taken from the first episode and Leonard's Fire in the Hole, which inspired the series, and it was delivered by Raylan after shooting Boyd.
The writers intended to have Damon Herriman and Margo Martindale to return as Dewey Crowe and Mags Bennett at some point during the finale but scheduling conflicts prevented it from happening.
Yost hoped that Boomtown' series regulars Donnie Wahlberg, Lana Parrilla and Nina Garbiras could appear at some point.
[19] In its original American broadcast, "The Promise" was seen by an estimated 2.24 million household viewers and gained a 0.7 ratings share among adults aged 18–49, according to Nielsen Media Research.
Club gave the episode an "A" grade and wrote, "Boyd and Raylan definitely aren't friends, and it would be a mistake to think they somehow are underneath all the sniping and subterfuge.
"[28] James Poniewozik of Time wrote, "It's only a kind of Western, and what has made it great–its true legacy from late godfather Elmore Leonard–is that its choicest ammunition has always been the word.
Raylan survived and made it to Miami, despite eventually losing Winona, while Ava managed to flee as far as California, giving birth to a baby boy that Boyd Crowder would never learn about, for the rest of his days preaching behind bars.
It was a definitive, entertaining conclusion to the story of Raylan's time in Kentucky, and I suppose that will make the show both easier to recommend to newcomers and more enticing to revisit one day for us.
"[33] Jeff Jensen of Entertainment Weekly wrote, "Justified departs as that rare series that succeeds as saga, as a cohesive, thematically clear whole.
"[34] Matt Zoller Seitz of Vulture gave the episode a perfect 5 star rating out of 5 and wrote, "What we did see was spare, concrete, and direct — basically an extended climax, a muffled detonation of a fuse that had been burning all season long.
"[35] Emily St. James of Vox wrote, "The most remarkable thing about the series finale of FX's Justified, which first aired Tuesday, April 14, is how it functions as both a capper for a six-season story and an almost perfect mirror of the show's very first episode.
"[36] Tim Goodman of The Hollywood Reporter wrote, "That finale should be considered a high point of the series (along with the masterful second season), because all endings on television are difficult and more so when you've got a protagonist/antagonist situation where both characters are, in some way, equally beloved by the audience.
In the end, Justified won't sit in the pantheon of shows like The Wire, The Sopranos, Mad Men or Breaking Bad, but somewhere high on the tier below.
"[37] Brian Lowry of Variety wrote, "The finale stayed true to the program's modern-cowboy ethos as well as the heady mixture of drama, comedy and tension that has always defined the dynamics among its key players.
"[39] James Queally of Los Angeles Times wrote, "'The Promise' is something of a muted finale for a show like Justified, but it's the right finish, not quite excellent but certainly memorable.
"[40] Sean McKenna of TV Fanatic gave the episode a 4.7 star rating out of 5 and wrote, "Justified, the sort of modern-day Western, may not have gone out guns blazing, but it succeeded in finding a satisfying ending that stuck true to its characters and story.
When viewers rewatch episodes years from now, I suspect that they will be shocked and delighted when they discover the myriad ways that the show built upon, doubled back on, reinvented, reflected, and re-imagined itself, all while staying true to a common tone and through-line.