- "Without me you're just a joke.. without a punchline"
- ―Jeremiah Valeska to Bruce Wayne
Jeremiah Valeska (also known as Xander Wilde) is a tritagonist turned main antagonist in the television series, Gotham. He is the definitive and "real" version of The Joker on the show (despite not directly being referred to as such), he is also the twin brother of Jerome Valeska who was hinted and thought to be the Joker, until he was finally killed off and replaced by Jeremiah. Jeremiah is yet to have a second evolution in his character where he finally takes "the Joker", as an alias.
Jeremiah was born to Lila Valeska and Paul Cicero and is the twin brother of Jerome Valeska
According to Jeremiah, Jerome would abuse and scare Jeremiah when he was little. Jeremiah would later recount that he realized Jerome was dangerous and knew he needed to get away from him so he sneaked away one night from Haley's Circus and had his uncle Zachary place him at St. Ignatius. Shortly afterwards, Jeremiah took on the alias of "Xander Wilde." He himself would later explain that he did this since he wanted to make it more difficult for Jerome to track him down, but Jerome, on the other hand, stated that he got adopted by rich people, therefore explaining his changed name.
He would then study at school and become an engineer. Four years after graduating, he started construction on his hideout, an underground maze bunker in a forest on the outskirts of Gotham City. The building took 6 years to complete.
At an unknown point in time, he met a woman named Ecco and hired her as his proxy and assistant.
Reunited With Jerome
Ten years after Jeremiah's graduation, Jerome breaks out of Arkham Asylum and kills their uncle, Zachary at the diner he owns for the location of his brother.
Jeremiah is then confronted by the stunned Captain Jim Gordon and Detective Harvey Bullock. They ask Jeremiah about him and Jerome, he tells them that once Jerome tried to kill him, so he ran away and changed his name to Xander Wilde. They then find out that he‘s holding Jerome captive, so they immediately order Jeremiah to let him go but he refuses to do so. After finding out that the Legion of Horribles is inside the building, and that they hypnotized Ecco, Jeremiah takes Jim and Harvey into the halls of his house, which were built like a maze that he’s the only one he can get out of. The three find Ecco there but, since she was hypnotized by Tetch, she gets into a fight with them, Ecco easily wins and takes Jeremiah to Jerome, but she’s eventually knocked out by Jim. Jeremiah then tries to escape but Jerome finds him. They have a verbal fight, in which Jerome tells he’s disappointed by what Jeremiah told about him, since, in his point of view, all of the things he said were lies. Jeremiah did agree that certain things that he told were in fact exaggerations of the truth. Jerome also tells Jeremiah that he’s going to drive him crazy and then kill him. Jim and Harvey eventually get to them, so Jerome runs away leaving Jeremiah behind. Jeremiah is later taken to the GCPD so that he can be put into protective custody.
Jerome took the Mayor, his wife, and a police officer hostage. He demanded that Jim bring him, Jeremiah and Bruce Wayne. Jeremiah is hesitant to go at first but later agrees. Jerome straps Jeremiah and Bruce into a chair. Jerome tells the crowd the story of him and Jeremiah and then cuts Jeremiah free. Determined to prove Jeremiah is just like him, Jerome hands Jeremiah the knife and tells him to take his best shot. Jeremiah tries to stab Jerome, who knocks him out with a single punch. Later, Jeremiah approaches Jerome’s body after he fell to his death. As Jeremiah walks away, Bruce asks him to let Wayne Enterprises fund his work. Jeremiah thanks Bruce and shakes his hand.
After Jerome's death, Jeremiah discovered a gift in his secret office and opened it. The gift is revealed to be a jack in the box in the form of a disfigured clown head that sprays Jeremiah with a special mixture of the laughing venom created by Jerome. The gas then eventually drives Jeremiah completely insane as Jerome's voice speaks to him in a recording coming out of the gift box, encouraging Jeremiah to be Jerome's successor and his ultimate revenge. Even though Jeremiah tried to fight the venom, it ultimately turned him into a complete maniac with pale skin and red lips.
Revealing himself as the Joker
Behind the Scenes
WB will not allow the show to use the name Joker for fear of diluting the brand. The visual representation of the source material is also extremely limited. Purple hair was considered at one point, before settling on extremely dark, vaguely green hair.
- When Cameron Monaghan was directly asked in an interview whether or not Gotham will be able to fully use "The Joker", he had this to say, "For now. That was the case when I talked about it prior. I will say we’ve been given certain liberties in this final season that we haven’t been given before that’s going to make itself pretty apparent as you watch it. All I’ll say is when you have an episode that’s a full-on Batman episode running around in the future, you’re going to have characters that you’ll expect to see. I don’t think it’s a spoiler to say at this point that it’s 10 years in the future — that’s been talked about openly by the producers and showrunners — I don’t want to say exactly what my role in that is, but it was kick ass." 
- In the same interview, he confirmed that he will only be playing Jeremiah Valeska, "Not triplets! No secret other twin. we’re seeing a very linear story arc with Jeremiah. Our point A is where we left off last season and our point B is a huge jump and I can’t wait for people to see it."
- EP John Stephens stated that he won't fully transform into the Joker - seeing as Cameron has made several in-depth statements contradicting this - it is most likely a way to avoid huge spoilers.
- Cameron has been confirmed to have a major appearance in the ten year time jump - presumably playing Jeremiah as the Joker after getting his evolution.
- According to executive producer John Stephens, Jeremiah is not the definitive Joker in Gotham's canon and the real Joker is watching the actions of Jerome, Jeremiah, and possibly a third, adopting them as inspirations.
- This statement is perhaps the closest to official canon until further notice.
- Cameron Monaghan said on twitter that whether Jeremiah becomes the Joker is purely up to the fans if he doesn't die by the end of the show.
- Jeremiah is referred to as "Mr J", which is one of the Joker's notable aliases, further supporting the fact that he will one day become the Joker.
- Cameron Monaghan was spotted with a more visible shade of Green Hair whilst filming Gotham Season 5.
- Cameron has confirmed that Jeremiah will be more unhinged in season 5.
- Jeremiah Valeska is the third incarnation of Joker (fourth if you count Jerome Valeska) to have a fully established identity. For many years it was only known that he operated as a caped supervillain called Red Hood that fell into acid during an encounter with Batman and was permanently disfigured, which this incarnation completely ignores. The first time the character's birth name was identified was Jack Nicholson's Joker in the 1989 Batman film, which was also carried over for Batman: Mask of the Phantasm and the animated series. The Jack Napier identity also appeared in Gotham Noir and White Knight. There was also a Martha Wayne version of the Joker from the 2011 "Flashpoint" crossover story arc, in which she was Joker in an alternative universe where Bruce Wayne was dead (having been killed by the mugger) and Thomas Wayne as Batman.
- Jeremiah's transformation and breaking into laughter is similar to the Joker's breakdown in The Killing Joke following his transformation. He also clutches his head in a very similar way to the iconic Brian Bolland panel.
- Jeremiah's motive to drive Bruce Wayne insane, and his method of doing so, is similar to how Joker tried to drive Commissioner Gordon insane after crippling his daughter.
- Additionally, he shoots Selina Kyle in a similar manner to how the Joker shot Barbara Gordon.
- Jeremiah is similar to Tim Drake from Batman Beyond: Return of the Joker, who was tortured and brainwashed by the Joker as a boy. But had the original Joker's consciousness implanted via microchip at the base of the neck, which could take over and possess him, physically transforming him like Dr. Jekyll and Mr. Hyde.
- This version of Joker is the fourth live-action version to appear on television: the first was in William Dozier's campy 1960's television series the second was in one of the Batman OnStar commercials and the third was a cameo appearance in the unaired Birds of Prey pilot.
- This is the youngest version of the Joker to date, being around 21-22 years old at the time of his transformation. Also, this version comes before Bruce Wayne becomes Batman. Due to rights issues down to Warner Brothers wanting to reserve Joker for their major DC film projects, limitations were set on the character of Jeremiah, such as him not being able to use the name "Joker" or even have pure green hair, which was started by actor Cameron Monaghan. To date, only Jared Leto and Cesar Romero have had bright green shades of hair. Instead, Jeremiah has very dark, only vaguely green hair and powdered pale skin. His wardrobe colors are also extremely subdued, only a few small parts with pure purple. This decision has not been received well, like many aspects of the show in general thus far. A small group of disgruntled yet devoted fans has taken to using a #LetGothamUseJoker hashtag in protest, which has yet to trend on any form of social media.
- However considering it's the show's final season, Warner Bros might let him be called Joker.