Not much is known about how the Joker came to be, there are various origins as who he once was; each ending with him falling into a vad of chemicles, and coming out permanently dying his hair green and bleeching his skin white; thus giving him the appearance of a clown, and of course making him criminally insane.
- Joker came back with his girlfriend, Harley Quinn along with Two-Face and The Penguin to get revenge on Pooh and his friends in Ryan Mitchell (Foster) Goes to Atlantis: The Lost Empire, Teenage Mutant Ninja Turtles, Teenage Mutant Ninja Turtles 2: The Secret of The Ooze, Home on the Range, 101 Dalmatians where they worked with Cruella De Vil along with Jafar, Iago, Maleficent, Ursula, Hades, and Jafar, Iago, Maleficent, Myotismon, The Grand Duke of Owls, Captain Hook, Shere Khan, Kaa the Snake, Clayton, Scar, Shenzi, Banzai, Ed, King Ghidorah, Brer Fox, Brer Bear, The Grand Duke of Owls and the villains. They worked with her again in Kids World's Adventures of 101 Dalmatians: The Series.
- Joker, Harley, Two-Face, and Penguin will team up with the Ancient Minister and his family, Jafar, Iago, Maleficent, Myotismon, Ursula, Hades, Dr. Facilier, Scar, One-Eyed Sally, Blather, Captain Hook, Oogie Boogie, Icy, Darcy, Stormy, Team Rocket, the Grand Duke of Owls and the villains to get revenge on Pooh, Ash, Bloom, Mickey Mouse, Simba, and their friends in Ryan Mitchell (Foster) & The Gang in The Halloween Tree.
- Joker and Harley will team up with Scar, Shenzi, Banzai, Ed, The Grand Duke of Owls, Jessie, James, Meowth of Team Rocket and the villains to work for King Jareth in Ryan Mitchell & The Gang Goes to Labyrinth.