"Good news: Joker's back to brighten up all your miserable lives!"
-The Joker's first line when entering the game.
"Let's put a few smiles on some faces, shall we?"
-The Joker's second line when entering the game.
Before becoming the Joker, he was a former lab assistant and failed stand-up comedian with a wife named Jeannie. Jeannie was pregnant with their first child, but due to his difficult life he started becoming erratic and mentally imbalanced. Jeannie, fearing for both her life and the life of their unborn child, went to the police, who helped her fake her death and move to Alaska to escape her husband. The man who would become the Joker was informed that his wife and child had died, forcing him to experience "one bad day".
The man who became Joker became Gotham's most sadistic and twisted crime boss and is insane, but also a genius, having knowledge of chemistry, physics, and engineering; Joker invents gag-based gadgetry whilst concocting criminal schemes. The Joker also cheats death frequently, having been thought killed several times only to come back and wreak havoc once more. He has many minions serving under him, most notably his self-proclaimed lover, Harley Quinn, his psychiatrist at the Arkham Asylum who fell in love with him there. The Joker is a mass murderer and has been known to kill many people, even his own henchmen.
Joker is widely accepted to be Batman's arch-enemy, which he is noted to be in the January/February 2012 issue of LEGO Magazine.
He and Saruman were the first bad guys that Lord Vortech summoned to Foundation Prime. He asked for their request to join his plan, offering them weapons he got from multiple other dimensions. Joker told Vortech that they would be crazy to refuse that offer. When Vortech failed to understand what that meant, the annoyed Joker told him that it means they were in on that plan.
He is sent by Lord Vortech along with Lord Business to invade Springfield. When Batman, Gandalf and Wyldstyle arrive at Mr. Burns' Mansion, where he meets with the trio and resurrects his gigantic mech: the Joker-Bot, using the Chroma keystone via a unit. He attacks them with his mech, however, they are able to defeat him and his robot. As he escapes with the Keystone, Gandalf attacks him causing Joker to drop the keystone but still escape to Foundation Prime. As soon as he arrives, he is seen with an ice bag, putting it at his head, regretting losing the Chroma Keystone and thus, giving Lord Vortech a warning about Batman.
The Joker is seen with other villains when the Thief explains Vortech his failure and he responds by smashing him.
Later on, whilst Batman, Wyldstyle and Gandalf meet face to face with Vortech, The Joker attacks the heroes with his mech's gun through vortexes. Vortech later opens a portal sending the Joker along with his minions who went to Vorton, badly damaged X-PO (telling the trio that "he put a smile on his face!"), and returned with the rest of the foundation elements. When Vortech creates The Tri he and the other villains decide to escape in the event that a similar fate was in store for them.
However, if you go to the Cloud Cuckoo Land, you can see The Joker, Master Chen & Lord Vortech's army dancing.
- The Joker was voiced by Mark Hamill in LEGO DC Super-Villains. He reprises his role in the game.
- Hamill also voices Chucky from the 2019 Child's Play movie, also reprising his role in the game.
- Despite Joker having his Rebirth head from the 2018/2019 LEGO sets, he reuses the 1989 movie outfit from the 1989 Batmobile set.