Real Name: Unknown
Occupation: Villain
Marital Status: Single
Base of Operations: Gotham City
Height: 6ft 5in
Weight: 192 lbs
Eyes: Green
Hair: Green
First Appearance: Batman #1 (Spring 1941)
Created By: Bob Knae, Bill Finger

The Joker was, at one time known as a criminal Called the Red Hood. While fleeing from Batman, the Red Hood fell into a vat of chemicals, from which he emerged with white skin, green hair, and a bizarre grin.

Though many have been related, a definitive history of the Joker has never been established in the comics, and his true name has never been confirmed. The most widely cited backstory can be seen in Alan Moore's The Killing Joke. It depicts the Joker as originally being an engineer at a chemical plant who quit his job to pursue his dream of being a stand-up comedian, only to fail miserably. Desperate to support his pregnant wife, the unnamed engineer agreed to help two criminals break into the plant where he was formerly employed. In this version of the story, the Red Hood persona is given to the inside man of every job (thus it is never the same man twice); this makes the leader appear to be the inside man, allowing the two ring-leaders to escape. The men convinced the engineer to wear it by saying it was out of their concern for his identity. During the planning, police contacted and informed him that his wife had died in a household accident.

Stricken with grief, he attempted to back out of the plan, but the criminals strong-armed him into keeping his promise. As soon as they entered the plant, however, they were immediately caught by security and a fatal shoot-out followed in which the two criminals were killed. As he tried to escape, the engineer was confronted by Batman, who was investigating the disturbance. In desperation, the engineer leaped over a rail and plummeted into a vat of chemicals. When he surfaced in the nearby reservoir, he removed the hood and saw his reflection: bleached chalk-white skin, ruby-red lips, and green hair. These events, coupled with his other misfortunes that day, drove the engineer completely insane, resulting in the birth of the Joker.

From the Joker's first appearance he has been willing (and eager) to wreak as much havoc as possible upon innocent people in order to claim the mantle of Gotham City's greatest criminal mastermind. Throughout his decades-long war with Batman, he has committed crimes both whimsical and inhumanly brutal, all with a logic and reasoning that, in Batman's words, "make sense to him alone."

Tthe Joker appeared at Commissioner Gordon's home one night and shot Barbara Gordon (aka Batgirl) in the stomach at close range, paralyzing her, and kidnapped the Commissioner. The Joker then stripped Barbara naked and took photographs of her injured body, which he would later show Gordon in his attempt to drive him insane; Joker sought to prove that any man can have "one really bad day" and become just like him. Batman rescued Gordon before pursuing the Joker, eventually cornering him on the rooftop. Batman tried one final time to reach his old foe, offering to rehabilitate him. The Joker refused, but showed his appreciation by sharing a joke with Batman, and the two began to laugh before Joker allowed himself to be taken back to Arkham.

One of the Joker's biggest impacts on Batman's life was the murder of Jason Todd, the second Robin. In his search for his long lost mother, Todd eventually found her in the captivity of the Joker. Joker beat Jason to within an inch of his life with a crowbar before blowing up the warehouse they were in. Joker escaped but Batman was left to find the lifeless body of the second Robin, a death that has haunted him since and intensified his obsession with his archenemy.

The Joker is convicted of a spree of murders where all the victims were left with the Joker's trademark grin. Though normally his plea of insanity would allow him to escape the death penalty, The Joker instead pleads innocent of the "amateurish" crimes, and is sentenced to death. However, Batman refuses to believe that the Joker committed the crimes because they are uncharacteristic of his arch-nemesis. Batman succeeds in identifying the real killer, who was attempting to frame the Joker.

A psychiatrist eventually begins to ponder that perhaps the Joker is in fact perfectly sane, and faking insanity so as to avoid the death penalty. This psychiatrist is Harleen Quinzel, the future Harley Quinn. As she tries to treat the Joker, he recounts a tale of an abusive father and runaway mother to gain her sympathy. It works all too well; she falls hopelessly in love with him, and allows him to escape Arkham several times before she is eventually caught. Driven over the edge with obsession, she turns into a criminal and the Joker's on and off girlfriend.

During No Man's Land, the Joker murdered Sarah Essen Gordon, Commissioner Gordon's second wife, by shooting her through the head as she tries to protect infants that he had kidnapped. Even the Joker finds no humor in his actions until Gordon retaliates by shooting Joker in the leg. The Joker begins to laugh, seeing the irony in losing the use of his leg after he paralyzed Barbara Gordon years earlier.

While in prison, the Joker believed himself to be dying and plans one last historic crime spree, infecting the inmates of 'The Slab,' a prison for super criminals, with Joker venom before escaping. He sets the super powered inmates loose on the world to cause mass chaos in their 'jokerized' forms. Meanwhile, he tries to ensure his "legacy" by defacing statues in his image and attempting to impregnate Harley Quinn. The entire United States declares war on the Joker under the orders of President Luthor; in response, Joker sends his minions to kill the President. The heroes of the world try to fight off the rampaging villains, while Black Canary discovers that Joker's doctor modified his CAT scan to make it appear that he had a fatal tumour in an attempt to subdue him with the threat of death. Meanwhile, Harley Quinn, angry at Joker's attempt to get her pregnant, is helping the heroes who rescued her to create a cure to the Joker poison and return the super villains to their normal state and eventually comes up with an antidote.

Nightwing eventually caught up with the Joker and, believing that Robin is dead, prepares to take the villain down once and for all. The Joker, happy to end his life by killing the first Robin, faces Nightwing in a physical one on one, a match that Nightwing easily dominates. Nightwing finally kills the Joker, just as Batman and his allies arrive. Refusing to allow the Joker to escape justice, Batman revives the Joker and sends him back to jail. The super criminals are all cured of their Joker venom.

After Jason Todd returns to life and takes over his killer's old Red Hood identity during the lead-up to Infinite Crisis, Jason asserts that the Joker is not quite as crazy as he leads people to believe. At the conclusion of Infinite Crisis, the Joker kills Alexander Luthor, hero of the original Crisis on Infinite Earths and villain of Infinite Crisis.

"One Year Later", Joker poisoned Commissioner Gordon and apparently having beaten Batman to death while disabled children he had taken hostage were forced to watch. He had also shattered the Bat-signal. However, the Batman he had beaten was a fake, an ex-cop in a Batman suit. Moreover, he was not dead, and pulled a gun. Batman was in time to save the Joker, but not before the bullet grazed his forehead. Batman took out his frustration by throwing him into a Dumpster.

Once the Joker resurfaced during the holiday season, he captured Robin and drove him through the city in a minivan. While driving, Joker aimlessly ran over innocent bystanders, killed a fast food manager in cold blood, and subjected Robin to physical and psychological torture. Eventually, Robin was able to play the Joker by starting a conversation about the Marx Brothers, which distracted Joker long enough for Robin to attempt an escape. Eventually he did, wrecking the minivan in the process. The body of the Joker was never found, so he remains at large.