The final moments of the Defiant in "The Changing Face of Evil", with the craft beginning to burn but ejecting escape pods, were shown with CGI achieved by Digital Muse, supervised by David Stipes. ( Cinefantastique, Vol. 32, Nos. 4/5, p. 74)

On the Defiant, Riker has Kalita set a course for the Badlands. He removes his false sideburns; he is Lieutenant Thomas Riker. Kalita congratulates Tom on his successful commandeering of the Defiant – but he says it is not over yet. The Dominion threat discovered in 2370 led Benjamin Sisko, now the commanding officer of starbase Deep Space 9, to pull the prototype vessel out of storage. The ship was assigned to his station, and it was officially christened that same year on Stardate 47538.5. The prototype was then equipped with a Romulan cloaking device, the only Federation starship to possess such technology as the result of an amendment to the Treaty of Algeron. ( DS9: " The Search, Part I") Thanks to the efforts of Chief O'Brien, many of the original ship's design flaws, such as its structural integrity field, were fixed. ( Defiant dedication plaque; DS9: " Shattered Mirror") Various rumors circulated about the origins of the Defiant. Noted Ira Behr, " I've heard all types of rumors about the Defiant." Many fans suspected the craft was invented by Ron Moore or René Echevarria, and that the writers wanted a ship on which to set more stories like those of TNG, despite the vessel actually predating the addition of Moore and Echevarria to the DS9 writing staff. Responding to such opinions, Robert Wolfe said, " The truth of the matter is the Defiant was an attempt to correct a deficiency in the runabouts […] It wasn't that we have to be like Next Gen . We were doing those kinds of stories on DS9 anyway. We just wanted to do what we do better and a ship will help us do that." ( Cinefantastique, Vol. 27, No. 4/5, p. 102) The craft turned out to be popular with fans. ( Star Trek: Communicator issue 142, p. 49) The main problem with the design at that stage was that it didn't look fast enough, so Meininger, a car enthusiast, got some posters of Ferraris and used them to help him design the "streamlined" look of the ship, making it very compact and sleek.The Maquis have been hearing rumors about shifting loyalties in the Cardassian government. Certain hardline elements were unsatisfied with the Federation treaty and are doing whatever they can to scrap it. We had our hands on an intelligence report outlining a suspected military buildup in the Orias system. A secret buildup that even the Central Command isn't aware of." Jones, Mark; Parkin, Lance (2003). Beyond the Final Frontier: An Unauthorised Review of the Trek Universe on Television and Film; Season Summaries, Characters, Episodes, Movies. Contender books. p.269. ISBN 978-1-84357-080-6.

According to Hutzel, during the early development stages of the ship, the Defiant was to be " a new hot battleship that would really set a new standard for an action ship in the series. First, there was lots of talk like 'How big is the Defiant ?' Well, we'll make it really small and really powerful, that it would be so powerful and scary, nobody would mess with it." (USS Defiant, DS9 Season 3 DVD special features) Eighteen ships of this class participated in Frontier Day celebrations over Earth in 2401. ( PIC: " Vox", " The Last Generation")Just when you thought Star Trek comics couldn’t get any bigger, we’re continuing to boldly explore new frontiers,” says Senior Editor Heather Antos. “Between the flagship title and DEFIANT, it’s safe to say that we have comics’ biggest Trek fans — Lanzing, Kelly, Cantwell, Rosanas, and Unzueta themselves — crafting what is going to be Star Trek’s biggest and boldest interconnected comics story ever. And this is only just the beginning!” The original MSD that appeared in " The Search, Part I" actually depicted an early concept design and did not represent the final iteration. was later replaced with an accurate MSD in such episodes as " Shattered Mirror", although it was used on displays until the end of Deep Space Nine. Drexler, who was responsible for creating the ship's MSD, rationalized "a 420′ [128.0 m] Defiant." [6] (X) In early 2375, the Defiant made a supply run to AR-558, a planetoid in the Chin'toka system under heavy siege by the Jem'Hadar. The Defiant crew provided a small reinforcement of the planetoid and helped disable many houdinis that had been plaguing Federation troops stationed there. ( DS9: " The Siege of AR-558") Defiant" is the 55th episode of the television series Star Trek: Deep Space Nine, the ninth episode of the third season. This episode guest stars actor Jonathan Frakes, in the role he had originated on Deep Space Nine 's predecessor series, Star Trek: The Next Generation. The episode aired in broadcast syndication on November 21, 1994. The Defiant was used by Doctor Lenara Kahn and her research team in an attempt to create an artificial wormhole. ( DS9: " Rejoined")

Jonathan Frakes always felt that the character of Thomas Riker should have returned to DS9 and that there should have been an episode where Kira fulfilled her promise to rescue him. The producers however, seemed to be uninterested in finishing the story arc, as in the fourth season pitch letter to freelance writers, Tom Riker appeared on the list of subjects that they were not interested in hearing about. ( Star Trek: Deep Space Nine Companion (p. ?))Ryan Whitwam (2015-01-19). "Star Trek: Deep Space Nine condensed: How to watch the most story-driven Trek". Mashable.com . Retrieved 2021-04-20. KAYLEENA PIERCE-BOHEN (2019-07-11). "Star Trek: 10 DS9 Storylines That Were Never Resolved". ScreenRant . Retrieved 2021-02-16.

Most notably, Defiant lays out the earliest moments of Worf’s captaincy in Starfleet, a captaincy that is, in Cantwell’s words, “frayed.” Cantwell points out that Worf’s future in Starfleet was always in question during TNG and DS9, thanks to his “insubordination and his record versus his loyalty and duty.” Although Sisko goes so far as to tell Worf that his actions mean that he will never be a captain in Starfleet, Defiant gives him that chance. For DS9, a digital model of the Defiant was built by Digital Muse, which was then borrowed by the visual effects artists of Star Trek: Voyager, as and when required. ( Cinefantastique, Vol. 30, No. 9/10, p. 80) A CGI Defiant was also used in DS9's title sequence.In 2256, the Defiant was assigned to patrol Sector 006 during the Federation-Klingon War. ( DIS: " Despite Yourself") Ira Behr commented: " The fans are already asking for Defiant play sets". ( Cinefantastique, Volume 27, Issues 2-12) Under the command of Worf, the Defiant was finally used for what the vessel had originally been designed for: fighting the Borg. In the Battle of Sector 001 in mid-2373, the Defiant assaulted an invading Borg cube from the Typhon sector to Earth and took severe damage. Sven Harvey (2020-01-03). "The Best Star Trek Deep Space Nine Stories". Den of Geek . Retrieved 2021-02-24.