Harvey Dent was a well known district attorney and friend of Batman in both of his identities. However after an experiment to rehabilitate criminals went wrong and scarred the left side of his face, he himself became a criminal that had a dual personality and made decisions of his actions with the flip of a coin.
Harvey was an old school friend of multimillionaire Bruce Wayne and they were the best of friends. They both grew up and became figures fighting for truth and justice; Bruce became the defender against crime as Batman and Harvey became a district attorney fighting to rid the city of criminals. He kept a double headed coin which was a memento from the first case he had won and kept it as a lucky charm.
Harvey however wasn't very popular with Bruce's youthful ward Dick Grayson as he always teased him and seemed to make Bruce forget he was around, but tried being nice to him for Bruce's sake.
One day Harvey was sent to Gotham State Penitentary where Batman and his partner Robin were also to view an experiment created by Professor Hugo Strange to rehabilitate criminals.
However the machine began to overload with so much evil that was being contained in a gas tank which was on the verge of exploding. Batman tried to warn Harvey, but he was too late and the tank exploded, spray gas in his face and scarring one side of it. Driven insane by what had happened, Harvey took on the persona of Two-Face and scarred one side of his lucky charm using it to decide his actions as a criminal, using heads (to do good) and tails (to do evil).
The Dynamic Duo kept fighting him many times and finally with the help of Bruce Wayne managed to get him rehabilitated and fixed the damaged caused to his face. Delighted with seeing his face normal again, Harvey promised that he would put right the wrongs he had done to Gotham City.
However it seemed as if Two-Face was still causing trouble as he had been seen once again by the Dynamic Duo, but when they confronted Harvey about the situation, he confessed, he was just as amazed about it as they were.
Later it was revealed that the effects of the gas from the evil extractor were taking over Harvey's subconscious mind, bringing back his Two-Face persona with Harvey being unable to explain his actions.
He eventually trapped the Dynamic Duo and found out their true identities. He had also released most of Gotham's criminals and decided to reveal the caped crimefighters' secret in return for money from the highest bidder. The criminals decided to put all their money together to find out the secret together.
Two-Face also tied Batman and Robin in a trap where they would be crushed with a giant replica of his coin, but they escaped and apprehended the other villains while Two-Face made his escape.
His other villainous objective was to cover Gotham City with the same evil gas that created him, turning it's residents into criminals like him. He piloted a plane armed with two large canisters containing the gas, ready to release it. However, the Dynamic Duo followed him, foiled his plan and cured all the people he affected.
The plane crashed near an abandoned chemical plant and Two-Face tried to escape. Batman followed him alone and saw to his horror that the gas was still taking effect and Harvey's face was scarred all over now. They fought and the plant started to catch fire, but Batman still had hopes of making his old friend good again and urged Harvey to fight off the evil that was taking control of his mind.
After a long struggle, Harvey's persona and face returned to normal again and together they escaped the blazing chemical plant.
Sometime later Harvey was invited to a party hosted by Bruce with his persona of Two-Face and his knowledge of Batman's true identity, apparently gone for good.
- Two-Face was planned to appear in the 1960s series in two episodes written by Harlan Ellison. However this was cancelled due to Two-Face's appearance being deemed too scary for younger viewers. So it became known as "The Lost Episode". Years later, the original storyline was published as a comic story called "The Two-Way Crimes of Two-Face" which appeared in the comic book series "Batman '66" before the future animated motion picture.
- Two-Face was voiced by actor William Shatner, best known for his portrayal of Captain James T. Kirk in the Star Trek franchise.