Nolan North voices Superman, Superboy, Match, Kru-El, and Zatara. The first four are justified since Superboy and Match are cloned from Superman, and Kru-El is an evil family member of Superman. Two supervillains that Superboy goes up against also voiced by Nolan North are Clayface and Baron Bedlam.
Khary Payton voices both Aqualad and Black Manta; justified in that they're father and son. He also voices Brick (who as of "The Prize" is a Suicide Squad member alongside Manta), Black Lightning, and Silas Stone.
Alyson Stoner voices both Bette Kane and Barbara Gordon.
Danica McKellar voices both Miss Martian and Marie Logan. Which makes sense in a way since Miss Martian based her looks and mannerisms on the latter.
Yuri Lowenthal voices Tempest, Lagoon Boy, Tommy Terror, and Icicle Jr. Tommy Terror and Icicle Jr. usually ended up on the same villain teams, whereas Tempest and Lagoon Boy are both Atlantean heroes.
Kelly Hu voices Cheshire, her mother Paula, and her baby daughter Liannote in season 2 only, Lian was recast to Zehra Fazal for all subsequent seasons.
Red Arrow and Guardian (both clones of Speedy/Roy Harper, according to Word of God) are both voiced by Crispin Freeman. This is played with in the episode "Salvage", where the now-retired Guardian is one of the people who confronts Red Arrow. And as of "Satisfaction" Speedy, now Arsenal, finally gets to talk with Red Arrow.
Jason Marsden plays both Impulse, Atom, and Danny Chase. Impulse and Danny interact a bit thanks to their involvement in the Legion's mission.
Fred Tatasciore ends up having a fight scene between himself with both characters he voices in episode 10 of Outsiders; Deathstroke and Metamorpho.
Mae Whitman voices both Wonder Girl and her mother, Helena Sandsmark.
Kari Wahlgren voices both Saturn Girl and Phantom Girl, and as of the first 4 episodes, almost all their dialogue is with each other!
Jason Spisak didn't get the role of Forager until after Wally was no longer in the main cast, but Forager did speak to Razer, when Spisak reprised the role from Green Lantern: The Animated Series.
Ben Diskin voices both Ma'alefa'ak and Orion due to the former tending to impersonate the latter.
Late in season 4 when the heroes fight the Phantom Zone Kryptonians, two roles by Denise Bouette, Rocket and Faora Hu-Ul, fight each other.
Phil Morris voices another two characters who are father and son, General Dru-Zod and Lor-Zod.
Beam Me Up, Scotty!: No, Batman did not say "Touch the Batmobile, and you're fired." in "Alienated". While it certainly sounds like something he would say, the line comes from a meme taking the scene where he sees Robin, Nightwing and Batgirl off before leaving out of context. In the actual cartoon, they all sincerely see each other off on good terms.
Channel Hop: Season 3 (Outsiders) aired on the DC Universe streaming service after Young Justice was cancelled in 2013 by Cartoon Network, thus allowing more creative freedom, a consistent release schedule, and a much lesser chance of being Screwed by the Network. This show hops again to HBO Max for Season 4 onwards after DC Universe was discontinued.
Content Leak: Season 4's final episode was leaked a week early in France and Quebec, with footage uploaded onto YouTube showing how the season ended, revealing Superboy being returned to normal, the subsequent defeat of General Zod, Faora, Non, and Ma'alefa'ak, Emerald Empress' escape, Lor-Zod's death, the wedding ceremony, the Light capturing the Kryptonians and turning Ma'alefa'ak over to Darkseid, the actual wedding itself, and Supergirl and Black Mary as Female Furies. While not every clip from the episode had been uploaded, it didn't help that the leaker managed to crack the French dub and restore English voice acting to the leaked copy, and while the channel showing the footage was eventually terminated, the footage simply resurfaced on another YouTube channel.
Co-creator Greg Weisman has said that Black Canary is his favorite DC Comics character, which is partly why she's one of the team's mentors on the show. She does get to be chairman of the Justice League in the season 2 finale, but her tenure is short lived in an onscreen capacity due to a Time Skip that shows Kaldur and Wonder Woman leading the Justice League instead by the events of season 3. She remains relevant by season 4 due to her involvement in helping Beast Boy recover from his depression.
Weisman has also said that Wally West is his favorite Flash.
Consciously averted in the case of Captain Atom. Weisman co-created and co-wrote the 1980s relaunch of the character, and when adapting his story for the tie in comics, asked staff writer Kevin Hopps what needed to be cut or kept, because he was too close to it. Weisman also stated that it was Vietti, not him, who suggested Captain Atom for League Chairman in season 2... though Weisman's choice was Black Canary.
Distanced from Current Events: On his Q&A page, Greg Weisman confirmed that COVID-19 evolved in very late 2020 rather than 2019 like in real life, ensuring season 4 and the Targets miniseries (both set in 2020) never address the pandemic in any way.
Fake Nationality: Ariel Winter once again voices Perdita, but she uses a European accent instead of her regular American voice.
Fandom Nod: In the series premiere, you have a citizen asking if Speedy is the Flash's sidekick, and when someone responds that he's Green Arrow's, the first guy says "that makes no sense", echoing a fair amount of comic book fans who didn't get Speedy's name (especially those introduced to him in crossovers).
Season 3's seventh episode, Evolution, which details Vandal Savage's backstory, was fittingly dedicated to Savage's original voice actor, Miguel Ferrer.
Season 4's first episode, Inhospitable, was dedicated to W. Morgan Sheppard, who voiced Sardath in season 2.
Season 4's eighteenth episode, Beyond the Grip of the Gods, was dedicated to René Auberjonois, who voiced Blockbuster's human form Mark Desmond in season 1.
Season 4's twenty-second episode, Rescue and Search, was dedicated to Ed Asner, who voiced Kent Nelson in season 1.
Lying Creator: Overlapping with Exact Words. Before the second season began airing, Greg Weisman stated that it would continue on minutes after the last season finale ended. While this is technically true, it is very misleading, since the scene that does take place right after the first season lasts less than a minute and is followed by a five year Time Skip.
The Original Darrin: A few of the original actors who weren't in the tie-in game, Legacy, came back for Outsiders, including Alan Tudyk as Psimon, Danny Trejo as Bane, Denise Boutte as Rocket, and Alyson Stoner as Oracle.
In "Drop Zone", The Brain/L-6 was voiced by Nolan North; in "Alpha Male" onward, he was voiced by Corey Burton.
Captain Marvel is voiced by Rob Lowe in "Alpha Male" and "Humanity", he is then voiced by his Real Life younger brother Chad in "Secrets". Chad then replaces Robert Ochoa as the voice of Billy Batson while in his teens and later young adulthood. In "Teg Ydaer!", an illusion of young Billy is then voiced by Eric Lopez.
Rocket was voiced by Miss Kittienote Kali Troy in "Usual Suspects," "Auld Acquaintance," and "Satisfaction;" Denise Boutte in "Intervention" and "Home Fires;" and Cree Summer in Young Justice: Legacy.
Flash (Barry Allen) was voiced by George Eads in Season 1 and the Season 2 episode "Bloodlines", but was replaced by James Arnold Taylor starting in the season 2 finale, who also replaced Tim Curry as G. Gordon Godfrey as the latter suffered a stroke in the time between Invasion and Outsiders.note As of 2021, Tim has recovered from his stroke enough that he's able to come back and do some TV roles.
On a more minor note, the Tribune in the Rimbor court was voiced by Miguel Ferrer in "War", but he was replaced by Nolan North in the finale.
In Season 3 (Outsiders), Beast Boy is not reprised by Logan Grove, as he left due to enlisting in the US Navy. He's replaced by Greg Cipes, Beast Boy's voice actor from Teen Titans (2003) and Teen Titans Go!.
When the Ultra Humanite appeared in season 1, he was voiced by Dee Bradley Baker when he just made gorilla noises. Come season 3, where he finally talks, and Greg Weisman takes over.
Amistad Ervin is recast from Khary Payton to Kurtis Mansfield in season 4.
Cyborg's father is voiced by Khary Payton, who is arguably considered the definitive Cyborg voice thanks to his work on Teen Titans and other DC productions. The crew seemed to go out of its way to point out the fact that Payton is not voicing Cyborg, who is instead voiced by Zeno Robinson. Additionally, Payton voices Ron Evers, who in the comics became an Evil Counterpart of Cyborg, but here is his classmate who yells Cyborg's Character Catchphrase "Booyah!" a lot.
Further, there was a whole team predecessor gag when Beast Boy has a dream sequence about his former team the Doom Patrol. Their members are voiced by the cast of Teen Titans, (and more directly Teen Titans Go!) who were Beast Boy's current team in those continuities.
Miss Martian's father is voiced by Carl Lumbly, who famously voiced her uncle Martian Manhunter in Justice League, the lead martian hero in a show that instead starred the adult heroes.
Production Lead Time: The amount of time spent developing Young Justice meant that it was not paying attention much to the changes going on in DC at that point, and a few ideas were thought of coincidentally from other productions that aired before Young Justice was revived.
Kaldur'ahm's comics counterpart, Jackson Hyde, was adapted into the comics by Geoff Johns before the show even premiered, due to the quicker lead time on comics compared to an animated series. Despite this, Greg Weisman has clarified that he does not consider Kaldur and Jackson to be the same character, even though they do sport many similarities.
The show originally entered production while an embargo that forbid the appearance of Wonder Woman and her other supporting characters if Wonder Woman was not a main character in the series was still going on. While Wonder Woman was still able to be featured in brief cameos with the rest of the Justice League, Greg Weisman could not use Troia, forcing him to use Miss Martian instead. The embargo was lifted while the show was still in production, finally allowing Wonder Woman to be fully voiced, but it was too late to insert Troia into season 1, and ultimately, he would have to wait until season 3 to feature her at long last. This likely also contributed to Wonder Woman's rogues' gallery being absent from the series, aside from several appearances by Devastation, one of her more obscure adversaries.
Young Justice's first season was still airing when the divisive New 52 had taken place, and thus continued to use a mixture of Silver Age and Post-Crisis depictions for characters alongside the various changes Greg Weisman made to them rather than using anything from the rebootnote For example, the Justice League was revealed in season 2, which aired in 2013 (two years into the New 52), to have originally formed to fight the Appellaxians, their obscure but faithfully accurate origin story in the Silver Age of Comics, rather than them forming to fight Darkseid as in the New 52. It was only when the show was revived that he started to use small amounts of New 52 and DC Rebirth concepts in seasons 3 and 4, like making New 52 character Harper Row a classmate of Halo and Forager, using Cyborg's New 52 backstory involving Apokoliptian technology being the source of his cybernetics (although he is not a founding Justice League member here), featuring the modern Jon Kent from DC Rebirth as a toddler, and Lor-Zod's portrayal as a villainous time traveler being derived from the character's Adaptational Villainy in Superman Family Adventures and Superman (Rebirth).
The eventual decision to kill off Wally West also was scrutinized as a result of this. Greg Weisman had planned to kill off Wally as early as season 1, but with many episodes from season 1 and the entirety of season 2 airing when the New 52 premiered with Wally absent around that time (his New 52 depiction, nowadays known as Wallace "Ace" West, would not be introduced until 2014, one year after season 2's finale had aired), he had no idea he had Demoted to Extra and eventually killed off the only version of Wally still being used in any medium at that point. As Wally was Greg's Creator's Favorite among speedsters, this was done primarily to establish the stakes of the series up to this point, replace Barry Allen (who had a more famous death among comic book audiences) as the character being killed off, and teach the lesson of heroes dying in the line of duty. The resulting death ultimately had no input from higher ups at DC (not even executive Dan DiDio, who saw Wally as a Creator's Pest, had communicated with him about the character). This also meant having to continue sticking to this decision, occasionally featuring the character in hallucinations, even when DC Rebirth and especially Infinite Frontier restored the original Wally West in the comics at long last.
Season 3 featured Darkseid in a flashback sequence where he invaded Earth millenia in the past, while season 4 had a shot of Lor-Zod turning his head in slow motion from the side to reveal he could perceive Bart Allen running very fast. Both shots were thought of and animated independently from similar scenes from Zack Snyder's Justice League, which featured Darkseid (or Steppenwolf in the theatrical cut) invading Earth (but being successfully fought off, unlike in Young Justice), and a shot of Superman turning his head towards Flash (mirroring Lor-Zod's battle with Bart), and their similarities are a complete coincidence due to Greg Weisman having not talked to Zack Snyder.
Krypton had beaten Young Justice to the punch in portraying General Zod as a black / Vathlo Island Kryptonian. However, this too was a coincidence, as Greg Weisman and Krypton's showrunner David S. Goyer had not interacted and shared ideas. What Greg Weisman did manage to do that no one else had done yet, however, was similarly depicting Faora Hu-Ul as black and Lor-Zod as a mixed race Kryptonian (the son of the black Dru-Zod and the white Ursa Zod).
From W.I.T.C.H.: Kelly Stables (Will and Arrowette), Kittie (Taranee and Rocket), Greg Cipes (Caleb and Beast Boy), Jason Marsden (Matt and numerous characters in Young Justice such as Impulse / Kid Flash, Atom, and Danny Chase), Kath Soucie (Nerissa and Queen Mera), Lauren Tom (Yan Lin and Thirteen), Cree Summer (Ember and Aquagirl), Alyson Stoner (Lillian and Batgirl/Oracle), Steve Blum (Blunk and Count Vertigo), Ed Asner (Napoleon and Kent Nelson), Vanessa Marshall (Eleanor Brown and Black Canary & Emerald Empress), Masasa Moyo (Ironwood and numerous characters in Young Justice such as Bumblebee and Cat Grant).
From The Spectacular Spider-Man: Josh Keaton (Spider-Man and Black Spider & Red-Hooded Ninja), Benjamin Diskin (Venom and Orion & Ma'alefa'ak), James Arnold Taylor (Harry Osborn and Flash/Barry Allen, Hawkman, Neutron, & Godfrey), Lacey Chabert (Gwen Stacy and Zatanna), Vanessa Marshall (Mary Jane and Black Canary & Emerald Empress), Steve Blum (Green Goblin and Count Vertigo), Andrew Kishino (Kenny & Ned and Mantis & Jax-Ur), Clancy Brown (Capt. Stacy and Agent Faraday), Ed Asner (Uncle Ben and Kent Nelson), Keith David (Big Man [first time] and Mongul), Bill Fagerbakke (Morris Bench and Bear), Miguel Ferrer (Silvermane and Vandal Savage), Crispin Freeman (Electro and Red Arrow, Arsenal, & Guardian / Jim Harper), Kelly Hu (Sha Shan Nguyen and Cheshire, Paula Crock, & Lian Nguyen-Harper), Peter MacNicol (Doctor Octopus and Professor Ivo & AMAZO), James Remar (Mr. Hardy and Icicle Sr.), Kevin Michael Richardson (Big Man [second time] and Guardian / Mal Duncan, Martian Manhunter, John Stewart, & Dr. Fate), Kath Soucie (Dr. Connors & Anna Watson and Queen Mera), Cree Summer (Glory Grant and Aquagirl), Danny Trejo (Ox and Bane), Thom Adcox (Tinkerer and Klarion).
From Gargoyles: Keith David (Goliath and Mongul), Thom Adox (Lexington and Klarion), Bill Fagerbakke (Broadway and Bear), Ed Asner (Hudson and Kent Nelson), Jeff Bennett (Brooklyn and numerous characters such as Alfred and Red Tornado), Marina Sirtis (Demona and Queen Bee), Clancy Brown (Wolf & Hakon and Agent Faraday), Kath Soucie (Princess Katherine & the Weird Sisters and Queen Mera), Brent Spiner (Puck and Joker), Cree Summer (Hyena and Tula), Gregg Rainwater (Nick & Mr. Maza and Tye Longshadow), W. Morgan Sheppard (Odin and Sardath), Zehra Fazal (Shari and multiple Young Justice characters including Halo, Windfall, Hawkwoman, and Cassandra Savage).
Star Wars Rebelsnote All Star Wars Rebels references occurred post-revival, so Star Wars Rebels did this trope to Young Justice pre-revival: Steve Blum (Zeb and Vertigo & Henchy), Vanessa Marshall (Hera and Black Canary & Emerald Empress), Brent Spiner (Senator Trayvis and Joker), Kath Soucie (Minister Tua and Mera), Peter MacNicol (Tseebo and Professor Ivo & AMAZO), Keith Szarabajka (Vizago and Mr. Freeze), Grey Griffin (Darja & Chava and multiple Young Justice characters such as Troia and Looker), Dee Bradley Baker (Admiral Konstantine and multiple Young Justice characters including Wolf and Chameleon Boy), Eric Lopez (Cadet Oleg and Blue Beetle / Jaime Reyes), Bryton James (Zare and Static), Tiya Sircar (Sabine and Dolphin), and Robbie Daymond (Eighth Brother and Wynnde)note However, Daymond was cast in Star Wars Rebels after Weisman left, so this may be unintentional..
Maggie Q was a Wonder Woman fan when she was younger.
Zeno Robinson was ecstatic at being cast as Cyborg.
Prop Recycling: An example that was later made a plot point, many episodes make use of a school bus that just so happens to have the same driver and students inside of it always in trouble, even the same shot of them screaming in peril. Zatanna's arc called attention to it by making it pop up in even weirder places to suggest the bus wasn't normal, before revealing it had actually been possessed by Klarion since its first appearance and travelling through time ever since.
Reality Subtext: Particularly in Season 3, where issues such as media control, human trafficking, rogue states, dictatorships, and so on are alluded to in some way. Of note is Lex Luthor serving as Secretary-General of the United Nations and recycling rhetoric from Donald Trump, such as "good people on both sides" and "fake news."
Or rather, recycled animation. The opening shot in episode 8 is lifted directly from Batman: Under the Red Hood. The building where The Team fights Clayface is the same one where the mobsters meet in the film.
Red Arrow's apartment is also the same one from the climax of the same film.
From DC Showcase: Green Arrow, Steve Blum and Ariel Winter reprise their respective roles of Count Vertigo and Princess Perdita. Though in the case of the latter, she actually goes for the European accent instead of her regular American accent that she used in the short.
Almost everyone in the main cast reprises their roles here despite the roughly six-year gap between seasons, the exceptions being Beast Boy, Hawkwoman, Lian Nguyen-Harper, Vandal Savage, Ultra-Humanite, and G. Gordon Godfrey.
Greg Cipes reprises Beast Boy in the place of Logan Grove, having played him originally in Teen Titans (2003) and various other adaptations.
From the DC Animated Universe: In addition to Alfred, Emmanuel Jacomy as Superman/Clark Kent, Alexis Tomassian as Robin/Tim Drake, Jean-Claude Sachot as Commissioner Gordon, and the late Marc Alfos as the second voice of Green Lantern/John Stewartnote he replaced Michel Vigné as the character in both parts of the JLU episode The Once and Future Thing.
From The Batman: In addition to Alfred and Gordon, Adrien Antoine as Batman/Bruce Wayne, Chantal Baroin as Batgirl/Barbara Gordon, Edwige Lemoine as Poison Ivy, Thierry Murzeau as Bane, and Christophe Lemoine as the Flash/Barry Allen.
From Batman: The Brave and the Bold: In addition to Batman, Batgirl, Flash/Barry Allen, and Alfred, Donald Reignoux as Nightwing/Dick Grayson AKA Robin Inote most specifically, he voiced the adult version of the character in The Knights of Tomorrow!, while the present-time version was voiced by Alexis Tomassian, Vincent Ropion as the replacement voice of Flash/Barry Allen, Christophe Lemoine as Blue Beetle/Jaime Reyes and the Flash/Jay Garrick, Michel Vigné as Aquaman, Marc Alfos as Red Tornado, Barbara Beretta as Black Canary, Jérôme Pauwels as Captain Marvel, Paolo Domingo as Billy Batson, Philippe Peythieu as Martian Manhunter, Xavier Fagnon as the Joker, and Thierry Murzeau as Black Manta.
From Superman/Batman: Public Enemies: In addition to Superman, Batman, Alfred, and Billy Batson, the late Marc Alfos as the first voice of Lex Luthor.
From Superman/Batman: Apocalypse: In addition to Superman and Batman, Delphine Braillon as Wonder Woman/Diana Prince.
Brazilian Portuguese dub:
From The Batman: Eduardo Ribeiro as Batman and Guilene Conte as Barbara Gordon.
From the DC Animated Universe: Guilherme Briggs as Superman (in the first and second sesons), Luiz Sérgio Vieira as Static, Elcio Romar as Vandal Savage (from the second season on); in Outsiders and Phantoms: Priscila Amorim as Wonder Woman, Andrea Murucci as Shayera, Luiz Feier Motta as Aquaman.
From the Arrowverse: Hélio Ribeiro as Jay Garrick (in Outsiders and Phantoms).
From Aquaman (2018): In Outsiders and Phantoms, Luisa Palomanes as Mera and Reginaldo Primo as Orm and his clone.
Screwed by the Lawyers: Donna Troy was originally supposed to appear in the first season but at the time of development neither Wonder Woman nor her supporting characters were allowed to be in anything in which they weren’t main characters due to the contract with her creator's estate. When Geoff Johns got a promotion in the early 2010s to Chief Creative Officer (the main liaison between DC itself and the various adaptations), he urged DC and WB to renegotiate the deal and they did. The timing didn't work out but they were able to use Cassandra Sandsmark in season 2 as after the time jump, it didn't make sense for Donna to be on a team with a different generation of heroes than her usual team.
Screwed by the Network: For whatever reason the show was very prone to schedule slippage, at least in the US. Cartoon Network took over a year (January 2011 - April 2012) to air the 26 episodes of the first season (not counting a two-episode preview in late 2010). Other countries even finished airing them months before the US did. In season 2, the entire DC Nation block got bumped to January 2013 with no warning near the start of October 2012, when it had only run for two weeks. So that's two back-to-back, three-month-long hiatuses with only two episodes aired in between. This also affected Green Lantern: The Animated Series, and what's worse, none of the creators were told. They all found out from fans on Twitter. Even DC Nation itself wasn't told; they updated their official Facebook asking how viewers enjoyed the block, and ended up having to delete it after it was swarmed by confused and angry fans. The episode was released on iTunes the next day, and peaked at #2 on their sales charts before being pulled, and no one knows why. Both shows were replaced by Beware the Batman and Teen Titans Go! after finishing their seasons. Any explanation for that either? Nope.
Screwed by the Merchandise: Paul Dini revealed on a Kevin Smith podcast that the toyline was indeed the reason for the cancellation. To be more specific, the show failed to sell enough toys. Because of the more detailed animation and the higher budgets it costs, toys have to sell well in order for an action cartoon to stay afloat.
This was likely the reason Outsiders and all subsequent seasons will be streaming-exclusive, out of a (possibly forlorn) hope it would ensure that no outside execs can screw them over like last time.
Serendipity Writes the Plot: As the show's budget became strained in later seasons, the show became increasingly reliant on scenes with still frames to save budget on animating every shot. The tendency to have characters communicate via telepathic links also started to see increasing use on saving the budget when it came to not having to actually animate characters talking.
Short Run in Peru: Several episodes of season 1 aired in other countries months before their airing in the US. Memorably, because of the infamous October hiatus, Brazilian fans took it upon themselves to record some episodes, subtitle them in English and share them on Youtube until they were shut down.
Teasing Creator: The descriptions for episodes of the second half of season 4 list minor details that happen in the episodes, and only minor details that happen in the episodes, to avoid listing actual plot details. Episode 24 ends up becoming the most vague of these with the weirdly phrased episode description "Team Trauma on Trombus!".
Technology Marches On: In "Image" when Superboy, Kid Flash and Robin wonder what "Hello Megan!" is that Miss Martian is referring to, Garfield Logan shows them an old videotape of the sitcom his mother starred in years before. Kid Flash snarks "Whoa, you still have VHS. Where's your 8 track?"
In season 2, Wally and Artemis adopt a sleepy white pit bull. According to the producers and Stephanie Lemelin, Artemis' voice actor, he's explicitly modeled after her own sleepy white pit bull, Bruceley. When asked what the dog's name was, Greg Weisman answered "I want to say Bruceley." And once the show was Un-Cancelled, Bruceley became the canon name of the dog.
In season 4, Beast Boy, recovering from the traumas in his life, unveils a therapy dog named Wingman, based on a dog that is frequently seen with his voice actor Greg Cipes.
Un-Canceled: Officially, as of November 7th, 2016.
Weisman has suggested that Kaldur isn't straight, and Season 3 depicted him in a relationship with the male Wynnde. Kaldur's exact sexual orientation is not specified further.
Greg also confirmed that Marie Logan in the show is either a lesbian or bisexual; when asked "is Marie a lesbian or bisexual?", he pointedly answered "Yes". This was also deduced by sharp-eared fans who noted that Queen Bee (who caused Marie's death during the Time Skip) was explicitly stated to only influence most men and some women, which Greg confirmed was indeed based on her victim needing to be sexually attracted to her for her powers to work on them.
Word of God: Normally, Greg Weisman is very tight-lipped, refusing to spoil things he hopes to reveal in the show itself, even minor details like who a notable character's real identity is. But every now and then, he may reveal something that is trivial enough to not be considered a spoiler.
Like many shows Greg Weisman has worked on, Young Justice will never actually end. Individual and seasonal storylines can wrap up, but as a real life story can never come to an end, the story of Young Justice will go on forever and continue to evolve.
Greg Weisman has a list of characters from least to most relevant in Young Justicehere. The list is set to have 782 characters in it when it's fully complete, with him posting a character in this list daily. However, most of the characters in the list are not only the notable characters, but various background characters such as civilians, Show Within a Show characters (such as Flaming C and Blue Falcon and Dynomutt), and characters only mentioned in a namedrop (like Peacemaker).
Written by Cast Member: Khary Payton, the long-time voice actor for Kaldur'ahm, wrote Episode 17 of Season 4, "Leviathan Wakes".
You Look Familiar: Jason Spisak, the voice of Kid Flash in the original series, returns in Outsiders as the voice of Forager.
Miscellaneous Trivia
Young Justice's large cast requires a lot of actors. While they cut costs throughout the series by hiring actors to play multiple characters and not writing dialogue for every character present, they still have way more actors and characters than most similar series. During a panel at Anime Vegas, Greg Weisman and Yuri Lowenthal explained how they got away with it: they took their retake budget and used it to hire more actors. The entire series was done without retakes. To compensate for this, they created what Lowenthal called a "walla library." Basically, they had every character actor get in the booth and record a series of grunts, fight sounds, exclamations, shouts of each other's names, etc. in a variety of different inflections, and stored them just in case they needed it during the sound mix, because they were using the money they'd spend paying the actors to come back and re-record over their mistakes to hire more actors.
This is the first appearance of Miss Martian in DC television.
This is the first appearance of Rocket and Icon in DC television.
This is the first DC animated TV show that features the first animated appearance of Lian Harper, or in this adaptation's case, Lian Nguyen-Harper.
Likewise, this is also the first official appearance of Cassandra Cain (renamed Cassandra Wu-San) in a DC TV show (at the time of her debut in Season 3, she had also already been announced to appear in the then-upcoming Gotham Season 5, and will make her big screen debut in 2020's Birds of Prey), not counting her unnamed cameo in Justice League episode "The Savage Time, Part 1".
Halo previously appeared in Batman: The Brave and the Bold as a voiceless cameo along with fellow Outsider members (including Katana, Black Lightning, Metamorpho, and Geo-Force, with the former three having already appeared in the show) in the Cold Opening to "Requiem for a Scarlet Speedster". And before that, a CrimeSyndicate version of Halo, known as Aurora, appeared in Justice League: Crisis on Two Earths as a member of the Crime Syndicate's version of the Outsiders, the Owlman Faction.
As mentioned with Halo, Geo-Force appeared in the Batman: The Brave and the Bold episode, "Requiem for a Scarlet Speedster", though unlike her, he actually spoke (sharing a voice actor with the show's Wally West, Hunter Parrish). He had also appeared as Brion Markov in Arrow as a One-Shot Character loosely based on him, instead being a scientist who developed a seismic device and turned it into a weapon for Malcolm Merlyn (otherwise known as Dark Archer) before Merlyn killed him. He had also appeared in the tie-in comics of the Teen Titans (2003) animated series.
This is the first official appearance of Hardware in a DC TV show. He had been namedropped in Static Shock episode "Gear", where Richie/Gear and Virgil/Static are brainstorming superhero names for the former after he develops superpowers. Richie suggests Hardware, to which Virgil states has already been taking.
This is the first animated appearance of Arrowette in DC television, not counting her silent cameo appearances in the online DC Super Hero Girls cartoon.
This is the second animated appearance of Traci 13, renamed as Traci Thurston aka Thirteen. She previously appeared in a cameo role in Teen Titans: The Judas Contract as a civilian that Jaime (Blue Beetle) has a crush on.
This is the first DC TV show to depict Batman along with all five of his current main "sidekicks" (Robin I/Nightwing/Dick Grayson, Batgirl I/Oracle/Barbara Gordon, Robin II/Jason Todd/Red Hood, Robin IV/Spoiler/Stephanie Brown, Batgirl II/Cassandra Cain (renamed Cassandra Wu-San), in addition to a civilian Bette Kane (if you count her as Batman's sidekick as opposed to Batwoman's) and an infant Damian Wayne).
This is the first official animated appearance of Batwoman (Kate Kane) in a DC television show. She previously made a cameo appearance in Batman vs. Robin as a corpse in a nightmare scene and was a major character in the sequel, Batman: Bad Blood.
