The episode "Serenity" establishes that the captain and his first mate Zoe Washburne, née Alleyne (Gina Torres) are veteran "Browncoats" of the Unification War, a failed attempt by the outlying worlds to resist the Alliance.

In the original pilot, "Serenity", Simon (Sean Maher) joins the crew as a paying passenger, smuggling his sister River Tam (Summer Glau) aboard as cargo.

Fox pressured Whedon to make Mal more "jolly", as they feared he was too dark in the original pilot, epitomized by the moment he suggests he might "space" Simon and River, throwing them out of the airlock.

Despite the series' short run, several recurring characters emerged from the inhabitants of the Firefly universe: Whedon developed the concept for the show after reading The Killer Angels by Michael Shaara chronicling the Battle of Gettysburg during the American Civil War.

Whedon and company felt they had to "serve two masters" by filming widescreen for eventual DVD release but keeping objects in-frame so it could still work when aired in pan and scan full frame.

[44] To obtain an immersive and immediate feel, the episodes were filmed in a documentary style with hand-held cameras, giving them the look of "found footage", with deliberately mis-framed and out-of-focus subjects.

[46] As Meyer recalled: "I think in the end the feel was that we wound up using a lot of places or exteriors that just felt too Western and we didn't necessarily want to go that way; but at some point, it just became the lesser of two evils—what could we actually create in three days?

"[55] To help illustrate the collection, the reviewer gave leitmotifs, or "signatures", various names, noting that "Serenity" recalls the theme of the show and is used when they return to the ship, or when they were meeting in secret; it was "the sound of their home".

The slide guitar and fiddle used in this piece are portable instruments that fit the lifestyle of the crew: "the music they make calls up tunes played out in the open, by people who were hundreds of miles away yesterday.

"[61] All nine cast members were chosen before filming began; while making the original pilot "Serenity", Whedon decided that Rebecca Gayheart was unsuitable for the role of Inara Serra, and shot her scenes in singles so that it would be easier to replace her.

[69] Canadian actress Jewel Staite videotaped her audition from Vancouver and was asked to come to Los Angeles to meet Whedon, at which point she was cast for the role of Kaylee Frye, the ship's engineer.

[78] Since the cancellation of the series, various cast and crew members have revealed details they had planned for the show's future:[85][86] Firefly consists of a two-hour pilot and thirteen one-hour episodes (with commercials).

[39] Prior to cancellation, some fans, worried about low ratings, formed the online Firefly Immediate Assistance campaign whose goal was to support the production of the show by sending in postcards to Fox.

Club cited several actions by the Fox network that contributed to the show's failure, most notably airing the episodes out of sequence, making the plot more difficult to follow.

[16] In addition, Firefly was promoted as an action-comedy rather than the more serious character study it was intended to be, and the showbiz trade paper Variety noted Fox's decision to occasionally preempt the show for sporting events.

The website's critical consensus reads, "Firefly earns its audience's adoration with the help of Nathan Fillion's dry delivery, a detailed fantasy world, and compelling storylines – even if it doesn't stand with creator Joss Whedon's most consistent work.

[104] Emily Nussbaum of The New York Times, reviewing the DVD set, noted that the program featured "an oddball genre mix that might have doomed it from the beginning: it was a character-rich sci-fi western comedy-drama with existential underpinnings, a hard sell during a season dominated by Joe Millionaire".

The review further notes the difference between the new series and other programs was that those shows "burst onto the scene with slick pilots and quickly deteriorate into mediocrity ... Firefly is on the opposite creative journey.

"All of Whedon's fingerprints are there: the witty dialogue, the quirky premises and dark exploration of human fallacy that made Buffy brilliant found their way to this space drama".

[5] A subsequent fan campaign raised over $14,000 in donations to have a purchased Firefly DVD set placed aboard 250 U.S. Navy ships by April 2004 for recreational viewing by their crews.

[134] In an interview on February 17, 2011, with Entertainment Weekly, Nathan Fillion joked that: "If I got $300 million from the California Lottery, the first thing I would do is buy the rights to Firefly, make it on my own, and distribute it on the Internet".

[136] Joss Whedon, Tim Minear, and cast members Nathan Fillion, Alan Tudyk, Summer Glau, Adam Baldwin, and Sean Maher reunited at the 2012 San Diego Comic-Con for a 10th-anniversary panel.

The characters each exhibit traits that exemplify core libertarian values, such as the right to bear arms (Jayne, Zoe), legal prostitution (Inara), freedom of religion (Book), logic and reasoning (Simon), and anti-conscription (River).

Hosted by Kari Haley and Les Howard,[141] The Signal is a fan-driven podcast dedicated to Joss Whedon's short-lived TV series Firefly (2002) and its film Serenity (2005).

Initially created as guerrilla marketing to promote Serenity,[142] the podcast features discussions about the franchise's role-playing game, fan fiction as audio dramas, and interviews (e.g. with PJ Haarsma,[141] Jane Espenson,[143] and Marc Gunn).

[149] Writing for Maximum Fun, Ian Brill praised The Signal as surprisingly professional with well-produced segments, though he unflatteringly compared Haley and Howard to Whedon's character Xander Harris: "They say mildly clever and cutesy things to each other and then sound tremendously satisfied with themselves while saying it.

When he and Leonard Hofstadter discuss their roommate agreement, they include a passage in which they dedicate Friday nights to watching Firefly, as Sheldon believes it will last for years (season 3, episode 22).

Castle has props from Firefly as decorative items in his home, has dressed up as a "space cowboy" for Halloween ("You wore that five years ago", cracked his daughter), speaks Chinese that he learned from "a TV show [he] loved", and has made rapid "two-by-two" finger motions while wearing blue surgical gloves.

[156][157][158] Con Man, a 2015 comedy web series created by Tudyk and co-produced by Fillion, draws on the pair's experiences as cult science fiction actors touring the convention circuit.

In January 2020, Fox's entertainment president Michael Thorn said that a revival series had been considered, but decided that since The Orville was on the air it would not make sense for the network to have two space franchises at the same time.