When developing the show, Bruce Timm toyed with the idea of giving the Justice League a uniformed look to their costumes and giving Wonder Woman a new hair style. When Timm mentioned it to DC president Paul Levitz, he said "Not the big three [Superman, Wonder Woman, and Batman]. You can do it to Green Lantern, you can do Flash, but not the big three." The designs were later used for the Justice Lords costumes.
The John Stewart Green Lantern was selected rather than the better known Lanterns, Hal Jordan and Kyle Rayner, not only because it would allow for an African-American member of the team, but the producers felt that the character's originally abrasive personality would have more dramatic potential.
Was originally to be titled "Justice League of America" after the incredibly popular JLA comic (Revamped by Grant Morrison). However, "Justice League" was favored to give the show a more universal feel.
Though a founding member of the Justice League in the comic books, Aquaman was left out of the cartoon series' line-up in favor of Hawkgirl, thus providing another female character. Aquaman appears only as a guest star.
As of season 3's beginning, the show's title changes to Justice League Unlimited, which is the name of the team as seen many years into the future in the series Batman Beyond (1999). With the show's title change, each episode now is only half an hour long and tells a complete story, and utilizes a rotating cast of DC Comics characters.
According to producer Bruce Timm, this version of John Stewart has been a Green Lantern for so long that the green radiation energy of the ring has actually infected his bloodstream-so that's why his eyes even glow green.
This is the fourth time that Bruce Timm and his team redesigned Batman. This version is similar to the classic Bob Kane Batman, which also is similar in design to the Batman Beyond (1999) design. Similarities between the two are the lengths of the ears on the mask, the figure and the boots having heels.
The entire Marvel Family and all related characters were unable to appear on the show due to legal reasons. An exception was made for Captain Marvel to make a one-time appearance on Justice League Unlimited.
The producers felt that the early Gardner Fox stories made the characters almost interchangeable and the more recent Grant Morrison stuff was just way too dark and complicated. Therefore (with the exception of "In Blackest Night" which was based on one of Fox's stories), they decided to create their own stories. However, what Timm did use from the Morrison run on JLA was the "dysfunctional family" atmosphere for the League.
Many cast members of the popular sci-fi show "Firefly" also voiced characters in "Justice League Unlimited". Nathan Fillion (Vigilante, Spy Smasher), Adam Baldwin (Jonah Hex, Hal Jordan, Rick Flagg Jr.), Gina Torres (Vixen), and Morena Baccarin (Black Canary).
The character models for some of the characters in the test footage was quite different from the final product. The Superman design used was identical to the models used on Superman (1996). Green Lantern had the same hairstyle and costume as the final design, but still possesses the dark green mask from the Superman draft model. The one with the most significant changes to his design was J'onn J'onzz. In the test footage he appears blockier, with a squarer jaw, a Kirbyesque line detailing his right cheek, and black eyes with red pupils (similar to the Joker's redesign for The New Batman Adventures (1997)). In addition, J'onn's color palate utilizes paler greens, blues and reds, and possesses none of the shiny highlights that have become a trademark of the series. Featured briefly commanding a robot that resembles the Golem (from Batman Beyond: Golem (1999)), Similarly, Lex Luthor had a craggy, Kirby-like detailing on his face, and his design is an early take on the updated purple-and-green jumpsuit uniform, indicating that the creative team was already planning on utilizing the Silver Age "mad scientist" Luthor, rather than the "corrupt industrialist" Luthor, from Superman (1996). Solomon Grundy looked a bit younger that on the final product and Cheetah looked more like her comic counterpart featuring long black hair.
Starting early in the second season of Justice League Unlimited, producers were restricted from using all Batman related characters besides Batman himself and a few c-list villains who didn't appear on Batman: The Animated Series (1992). This was because a new unrelated show called The Batman (2004) was set to air on another network, the WB.
To make this series less like Super Friends, the producers decided not to use any sidekicks/Junior members or any animal mascots on the team. They were initially going to include Robin, Impulse, and Natasha Irons (Steel's little sister) as a female Cyborg as Junior members when creating test footage for Kids WB, but decided not to when Cartoon Network green lit the show and didn't request Junior members.
Green Lantern and Hawkgirl started to have a romantic relationship grow as the series progressed. The producer's decided to pair these two characters together since both no-nonsense warrior types with Green Lantern having a military background and Hawkgirl coming from a very warlike planet. This relationship was originated for the show as the two characters never had a romantic relationship in the comics.
When developing the show, the producers learned from Marvel's mistake on Avengers: United They Stand (1999) by not including Captain America, Iron Man, and Thor. This show always intended to include Superman, Batman, and Wonder Woman. According to Bruce Timm, DC Comics President Paul Levitz was behind them all the way saying right off the bat, 'It's going to be hard to get the rights to all of these characters, but you have to have Superman, Batman, and Wonder Woman. And whatever it takes, we'll make that happen.
The futuristic look of the Metropolis, seen in Superman (1996) had been redesigned to look more modern and realistic. However, when the show changed to justice League Unlimited, the futuristic design of Metropolis was brought back.
When developing the show, Bruce Timm thought it would be a good idea to have a CGI intro sequence because he liked how his character designs looked in 3D after seeing game footage for Batman: Vengeance (2001).
At the request of DC comics, the red of The Flash's costume was a darker shade than it was on his initial appearance on Superman (1996). Also the circle around the flash symbol on his chest was changed from black to yellow.
The Justice League's headquarters is the Watchtower, which is from the modern mythos, but it's also the Justice League Satellite from the silver age. The producers decided to use a combined version of the two headquarters because they though it just didn't make sense to put the team all the way out on the moon, where the watchtower is located in Grant Morrison's JLA comic,-it's just a little bit too far away.
Though intended to incorporate both the previously aired Batman: The Animated Series (1992) and Superman (1996) cartoon histories, the creative staff initially decided to ignore Superman: In Brightest Day... (1999) so as to not confuse viewers with two different Green Lanterns. This plan was later reconsidered. In "Hearts and Minds", the Green Lantern introduced in the Superman series, Kyle Rayner, is briefly mentioned as being a Green Lantern Corps member and appears in "Hereafter". In "The Return", Rayner is shown in action with the Corps as a speaking part. In "The Once and Future Thing: Part Two: Time, Warped" Chronos' tinkering with space-time causes John Stewart to briefly morph into Hal Jordan, the original comic's Silver Age Green Lantern who was not previously seen in Batman: The Animated Series (1992), _"Batman: Gotham Knights" (1997)_, Superman (1996), or _"New Batman Superman Adventures, The" (1997)_.
In designing Wonder Woman for the show, the creative team stuck mainly to the modern, Post-Crisis incarnation of the character that debuted in 1987. The world of Diana and the Amazons was written to be closer in tune with the original Greek and Roman myths while, at the same time, incorporating elements from the previous versions of the Wonder Woman mythos. However, her origin was adapted to fit into with the events of the White Martian invasion; meaning that elements such as the contest to decide which Amazon would become Wonder Woman and Diana's sanctioned mission as Ambassador to Patriarch's World were eliminated.
The Justice League uses their ultra-advanced spacecraft. The reason the producers gave them a spacecraft is that the Watchtower is out in space, so they needed a way to get to and from it, but they didn't want to do transporters (though the team did use them in the comics for some time).
To make the show unique, the producers decided not use the established Superman and Batman villains that they had done in all the Superman and Batman shows that they had done. They figured this show presented a really good opportunity to choose from a wealth of DC villains such as Vandal Savage, Dr. Destiny, Felix Faust and Gorilla Grodd. The only established Superman or Batman villains they planned on using were Lex Luthor and the Joker; both were in the Injustice Gang. They wanted to try something different for as long as they could, before going back to using the Batman and established Superman villains in Season 2.
When developing the show, the producers intended on using The Key, but scrapped plans to use him because his powers were a little too close to Dr. Destiny's. The Key nearly omitted from the DCAU until he made his long awaited debut as a member of Grodd's expanded Secret Society. In addition, the creative team updated the Key's look; giving him a Jack Kirby-inspired update of his classic Silver Age costume.
When the series began, Kyle Rayner was the active Green Lantern in the JLA comic. After the animated series continued to gain in popularity, John Stewart was brought back to the comics early 2003 and had replaced Rayner as the Green Lantern in the JLA comic. Stewart was even redesigned to feature the fade haircut and uniform design from the animated version.
The show did a two-part cross over with Static Shock (2000). The crossover was originally going to be with Teen Titans, but since the crossover would have aired before the Teen Titans (2003) animated series premiered, a crossover with the Justice League was done instead.
Since Batman: The Animated Series (1992) and Batman Beyond (1999) all went out with a 'poof', the creative team planned on ending each season with a bang as if it their last, just in case. The producers decided they wanted to have a satisfying conclusion to each season, but still keep the door open to continue the series should get picked up.
When developing the show, the producers had so many characters to use (with 7 main characters more than any of their previous DCAU shows) and they wanted to up the ante on the scale and the action, so they decided early on to do extended storylines, so every episode is one part of a two-parter or even a three-parter.
Green Lantern's characterization differed from the comic book version of John Stewart by being a former United States Marine and having not been explicitly revealed to have studied architecture. Since then the comic book version has been updated to include a being a former United States Marine.
Glen Murakami and James Tucker though they needed a new Superman design for the show thinking he should be a little more mature, a little more rugged. Bruce Timm pushed to just use the old Superman model from Superman (1996), but eventually went along the idea and gave him a bulkier physical appearance with strong cheekbones and little tiny dashes under his eyes, which are supposed to give him a little bit more of a comic book 'squinty' look; makes him look a little bit older. Starting in Season 2, the strong cheekbones and dashes under the eyes were removed.
For this series, AMAZO got a complete redesign. Producer Bruce Timm thought AMAZO's design in the comics was really old-school, real garish and bizarre and not very modern at all. Therefore, he came up with a new design that was a combination between Gort from The Day the Earth Stood Still (1951) with the morphing powers of the T-1000 robot from Terminator 2: Judgment Day (1991). His creator, Professor Ivo-himself a classic Justice League villain-never makes an actual appearance in the animated series, and it is unknown to what end the android was created.
Cheetah was supposed to have been killed by Solomon Grundy in her original appearance, but was shown to have survived due to an animation mistake. Cheetah continued to make appearances throughout the rest of the series.
For "Starcrossed", the creative team wanted to use Hawkman, but was denied by DC comics since the character acted more like a villain in that story. The character was renamed Hro Talak (an anagram of Katar Hol) and though loosely based on the Silver Age Hawkman, he wasn't allowed to be Hawkman.
The character Aresia's is based two individual characters, both who use the identity of Fury in the comics. This animated version is based more upon the Helena Kosmatos version, but possesses a visual design based upon the original Fury.
Originally, the creative team wanted to feature the old Justice Society, but DC had some issues with their use in this particular story, so they compromised and made the Justice Guild of America who are inspired by the golden age Justice Society.
The show had a spin off comic called Justice League Adventures which ran for 34 issues before being restarted under the title Justice League Unlimited which ran for 46 issues before being canceled in 2008.
The Superman, Batman, Hawkgirl, and Green Lantern Justice Lords costumes are alternate looks of the future costume changes of the regular: Superman changes his costume to a black and white kryptonian costume and gets attacked by Starro, Batman changes to the _"Batman Beyond" (1999) costume with the same shaped bat symbol, Hawkgirl uses a thanigarian inspired mask in "Starcrossed", and Green Lantern shaves his head following the events of "Starcrossed".
After putting in a 26 episode order for Seasons 3 & 4, Cartoon Network wanted to re-brand the show somehow, and they were very vague about that. They just wanted to do something to differentiate Season Three from Seasons One and Two, to let the audience know it's a fresher show. Series producers Bruce Timm decided to expand the Justice League.
After using the Aquaman's classic design on Superman (1996), the producers warmed up to his redesigned look from the comics with the long hair and beard with hook hand look and decided to use it for the show.
After appearing in the recent Grant Morrison's JLA comic, The injustice Gang made their animated debut on this series and the team consisted of Lex Luthor, the Ultra-Humanite, Copperhead, Star Sapphire, Shade, Cheetah, Solomon Grundy, and The Joker. They appeared again in Fury, minus Lex Luthor, Joker, Cheetah, and the Ultra-Humanite; but with Aresia and Tsukuri added to the team. Since most TV viewers were familiar with the Legion of Doom, the team was never referred to on screen as the Injustice Gang until the Shade made a reference his old team to the Secret Society.
The show's creative team, even going back to Superman (1996), had no intention of using Doomsday. They only decided to use him to show how ruthless the Justice Lord Superman is. They later brought back Doomsday during the Cadmus conspiracy arc and the creative team retrofitted his origin to fit together with the Cadmus conspiracy arc, creating a new back-story that works much better than the centuries-long, confusing arc from the comics.
There were several characters like Blue Beetle, Firestorm, Black Lightning, the Spectre, and the Phantom Stranger that were not allowed to appear on the show due to rights issues making them off limits.
The creative team choosing to pay homage to both incarnations of Despero, combining the pre-crisis mental powers and the throne of Kalanor with the post crisis hatred and the more physically imposing body type to create an amalgam possessing the most memorable traits of both. They also altered his skin tone from pinkish-purple to straight purple and an gave him an eloquent, poetic slant to his speech pattern.
The Crime Syndicate were initially going to be used in this series, but as the writers continued to develop the story, the more they realized they were changing the basic idea of the Crime Syndicate so much that they it wouldn't be worth calling them that. The team ended up being literally an alternate universe version of the Justice League called the Justice Lords. The real Crime Syndicate never appeared in the series.
There was a Justice League DTV movie in the works, called "Justice League Worlds Collide", featuring the Crime Syndicate and takes place between Season 2 and Season 3. What happened was, the Home Video division commissioned a Justice League DTV movie, right around the time work began for Season 3 so, the original plan was to do the DTV and Season Three concurrently . Dwayne McDuffie and Bruce Timm came up with the story, McDuffie wrote a terrific script, Timm designed loads of new characters, they started story-boarding, Andrea Romano had assembled a killer cast, and were just getting ready to record it, and then Home Video slammed on the brakes, and it was put on the shelf for the time being. The Season 2 finale, was supposed to air in 2003, but was held back until May 2004 around the time the DTV was supposed to be released. The project did see a light of day heavily re-written as the non-DCAU Justice League: Crisis on Two Earths (2010).
Cartoon Network felt that multi-parts are limits the show to doing big storylines where so much time and effort has to be put into this one idea and sometimes getting in danger of making stories long just for long's sake. With Justice League Unlimited they were able spotlight the characters and give everyone a moment in the sun in one episode as opposed to doing giant arcs where lots of things happen and there's so much to keep track of. In the bigger sense, multi-part storylines are great, but they are bad for people who missed a few parts and wonder what's going on when randomly tuning in to an episode. Also, if a network is airing reruns and not doing so in order, there's a risk someone seeing one part of something and never seeing what happens next or how it all began.
The creative team literally went through DC's Who's Who books to pick out characters to be used in the expanded Justice League. They made a list and asked DC Comics for permission to use a whole pile of characters at the beginning of Justice League Unlimited. They occasionally thought of something new as they went along, and continued to ask on a case-by-case basis. Likewise, occasionally they'd sit on something too long, and DC would tell them a character can't be used anymore. Considering the complexity of DC's many licenses, they bent over backwards to get allow as many characters to be used as possible.
The original inspiration for the new title intro for early episodes of Justice League Unlimited was the Space: 1999 (1975) main title sequence. The goal was to do a throwback to what old TV shows, like Mission Impossible and all the Quinn Martin shows, used to do with 'episode-specific' titles. Not too long after it's debut, it became a standardized title sequence with regular non-episode specific clips because it was extremely difficult to find spectacular but non-spoiler shots for each 22-minute cartoon. The teaser end-titles, which featured clips from the next episode, stayed the same as per Cartoon Network's request.
Huntress' original costume was based on the Jim Lee costume and featured a bright purple cape, shoulder pads, and mask with no white except for the eye slits. When Huntress finally had a full role, her costume was changed to be an exact copy of the Jim Lee costume.
Once Season 3 started the show started to use CGI vehicles. Despite producer Bruce Timm's resistance to CGI, nobody wanted to animate vehicles by hand, and the overseas companies had been begging the production team to switch to 3D vehicles for years.
In Justice League Unlimited, Wonder Woman gets her invisible jet. There actually was going be an origin story to explain where it came from on the planned Justice League direct to video movie by that was canceled.
Originally the creative staff didn't think the first 26 shows of Justice League Unlimited were going to connect in a season-long story arc until they got to "Fearful Symmetry", and realized they already had a story arc in place. They realized that there were all these plot threads that they had going quite a ways in the past from the entire DCAU that could connect into a bigger, broader story arc, and decided to focus all their energy on that. And, by the time Season Four started, it became quite the epic story arc.
For Justice League Unlimited, the scope of Cadmus' vision has expanded somewhat from the cloning facility that it was in the comics into a paramilitary organization dedicated to standing against the perceived threat that the Justice League poses...though the organization's genesis can be traced back to the early days of Batman: The Animated Series (1992).
"Epilogue" was originally made to not only conclude the season, but to bookend the entire DCAU. That's why the final scene emulates the first scene in "On Leather Wings"-the first episode of Batman: The Animated Series (1992)
Originally, S.T.R.I.P.E.'s armor was of considerable size, large enough to let Stargirl sit on his shoulder and to where Pat Dugan had to climb up to get in the armor. However, in the final season, S.T.R.I.P.E. got new armor that appeared to be a perfect size for Pat to fit in.
In the final season, the Justice League have a new ground base called the Metrotower It's kind of a cross between the United Nations building and the Hall of Justice from Super Friends (1973). In Batman Beyond (1999) there's actually a Metropolis Tower on the ground. Even though it looks different, it's clearly a later version of the same building. They still have their orbiting Watchtower though.
In the final season, Supergirl got a new costume to closer resemble her cousin Superman's costume. In reality, producer Bruce Timm changed Supergirl's costume because he thought her original costume looked dated.
During Season 5, Aquaman and all related characters could no longer be used on the series due to a TV series pilot that was being developed for the WB. Black Manta still got to appear on the show, but has name had to be changed to Devil Ray to avoid rights issues.
This version of Speedy's design was based on his modern redesign from Teen Titans (2003), but with slight adjustments. This version of Speedy has a different "S" symbol on his uniform and still uses green colored arrows.
When the Crimson Avenger appeared in the final season had a new costume that was slightly different from how he appeared in earlier episodes of Justice League Unlimited. The new costume replaced the black business suit and fedora hat and instead featured crimson trench coat and crimson hat.
The original Watchtower is destroyed in the climax of Starcrossed. When the series resumed under its new title, Justice League Unlimited, a new, much larger Watchtower was unveiled and it was designed to accommodate a large number of support staff and the expanded roster of League. The Watchtower now has a large kitchen, meeting, and medical facilities, and it is strongly implied that some members of the League live on the station full-time.
During a meeting with DC comics vice president Paul Levitz and the show's creative team, Levitz suggested that somewhere in the course of the show they should do a big stunt where one of the major characters gets killed or one of them betrays the League. They quickly narrowed down the list of suspects to Hawkgirl and though it would be much more of a tragedy if she betrayed the League against her better judgment; if she was conflicted about it and not just out-right evil.