Random Trivia For This Title:
- In the prison the guard presses a red phone on his smart phone, possibly a nod to the 'Bat-phone' in Batman: The Movie and the 1966 [Batman] series.
- Extensive reshoots in London and Los Angeles in mid-2017 added a cost of approximately $25 million to the film's budget. Henry Cavill worked on the reshoots and Mission: Impossible - Fallout at the same time. He had to sport a mustache for his role in the latter project, however Paramount refused to let the actor shave it off for the time he played Superman again. This meant that Cavill's facial hair had to be digitally removed in post-production.
- In the Kryptonian ship base, while checking Barry Allen's credentials, the name Wesley Shipp comes up on the screen. John Wesley Shipp played the original Flash in the CBS series.
- When the film got shown in Iceland (which uses subtitles rather than dub for films with non-Icelandic languages), Jason Momoa's pronunciation of his single line of Icelandic was deemed so unintelligible that it had to be subtitled into Icelandic (often resulting in a big laugh by the audience).
- Director Zack Snyder and his wife producer [?] Deborah Snyder stepped down from finishing the film, after the suicide of Zack Snyder's daughter in March 2017. They tried to remain on the film as a way to work through the difficulty, but decided after two months to step away from the project to spend time with their family. Joss Whedon, who had signed on for Batgirl, took over as director, managing additional scenes that need to be included in the final cut. Warner Brothers stated that Joss would direct and write in the same style as Zack so there wouldn't be any tonal shifts or obvious changes in style. However, Joss Whedon controversially fired Zack Snyder's composer Junkie XL, and replaced him with Danny Elfman.
- Ciarán Hinds portrays Steppenwolf in performance-capture. Hinds was unfamiliar with using the technology and got advice from his friend Liam Neeson, who had earlier done performance-capture acting in A Monster Calls.
- In October 2007, George Miller had cast the Justice League completely, with D.J. Cotrona as Superman, Armie Hammer as Batman, model Megan Gale as Wonder Woman, rapper Common as Green Lantern/John Stewart, Adam Brody as the Flash/Barry Allen, Santiago Cabrera as Aquaman/Arthur Curry, Hugh Keays-Byrne as the Martian Manhunter (J'onn J'onzz), [?] Tereasa Palmer as Talia al Ghul, and Jay Baruchel as Maxwell Lord. However, the film was shelved during production.
- Holt McCallany, who plays the burglar in the first scene with Batman, said the scene was written and shot by Joss Whedon as comedic, but Warner Bros. preferred to open the film with a more serious tone, and the scene was re-edited. When McCallany returned home to New York, he found a bottle of his favorite champagne at his door and a note from Whedon that said, 'To battles lost. Gratefully, Joss.' McCallany appreciated Whedon's gesture and had the letter framed.
- Due to the running time backlash of past DC movies, Warner Bros demanded a film under 2 hours without credits. The final running time for Justice League is 119 minutes.
- Wonder Woman first appears in the film standing atop a statue of a goddess. This is the Greek goddess Themis, or Justitia to the Romans, better known in modern society as Lady Justice.
- Billy Crudup plays Barry Allen's (The Flash) father Henry in this film. However, before appearing in the DC Universe, Crudup initially auditioned for and was a top contender for the role of Bruce Wayne/Batman in Batman Begins before Christian Bale was cast. Crudup also portrayed a DC Comics superhero (Dr. Manhattan) in the film, Watchmen.
- Laurence Fishburne was asked to reprise his role as Perry White for a cameo, but scheduling conflicts with other projects made him unavailable on the day filming was supposed to take place.
- This movie was initially going to be split into two parts: Justice League Part One and Justice League Part Two, with an alleged singular continuing story line. But by the time filming the idea of the film being in two parts seemed to have quietly gone away, and it is now rumored to be two self-contained movies with two related but separate plots.
- Zack Snyder and Ray Fisher both stated that Cyborg was going to be the heart of this film. However, when Joss Whedon was hired for reshoots, most of Cyborg's scenes were cut.
- In one scene, Alfred (Jeremy Irons) says to Bruce Wayne (Ben Affleck), "One misses the days when one's biggest concerns were exploding wind-up penguins." This is a reference to Batman Returns, where Batman (Michael Keaton) goes up against Catwoman (Michelle Pfeiffer) and the Penguin (Danny DeVito) who had an army of penguins wearing exploding rockets with a plot to destroy Gotham City. The composer of Justice League, Danny Elfman, also composed the original Batman & Batman Returns musical scores and he utilizes parts of them in this film.
- When the three DC main heroes (Wonder Woman, Batman, Superman) make their first public appearance in the film, a part of their theme music from their respective films (bvs_justice, Batman, and Superman - all their cinematic debut films) plays.
- The scene in which Barry Allen/The Flash is grumbling that Bruce Wayne/Batman is sitting in his second favorite chair is an inside joke about "Sheldon's Spot" from [The Big Bang Theory]. Sheldon is a big fan of The Flash and Cicso Ramon, ally and friend of The Flash also wears t-shirts with Sheldon's quotes in TV series [The Flash].
- Marc McClure who played Jimmy Olsen in Superman has a cameo as the officer at the prison.
- As an April Fool's Day joke, production said Zack Snyder had left the project and that George Miller would be taken up the directing duties. The feedback was quite positive. However, when Joss Whedon replaced Snyder due to the death of Snyder's daughter, feedback was sincerely sympathetic.
- This is Danny Elfman's twelfth time scoring a superhero film, after working on Tim Burton's Batman films, Barry Sonnenfeld's Men in Black films, Sam Raimi's Spider-Man films, Hulk, Wanted, Hellboy II: The Golden Army and Avengers: Age of Ultron.
- Joe Morton who plays Silas Stone in this film and the father/ creator of Cyborg, also starred in Terminator 2. In both movies he uses futuristic technology that in turn lead to the creation of cyborgs with metal parts and red eyes: the Terminators themselves in Judgement Day, and Cyborg his son in Justice League.
- Lana Wachowski and Andy Wachowski (now Lilly Wachowski) were, at one point, considered to direct this film.So was Ben Affleck at one point.
- At one point a newspaper cover story announces that certain beings have returned to their alien worlds. Two of them are David Bowie and [?] Prince, both of whom died and who were considered eccentric icons of world culture.