The two-headed silver dollar was originally owned by mobster Vincent “The Boss” Maroni, who kept it as a lucky charm. When Maroni murdered rival mobster “Bookie” Benson, he left the coin behind, which became used by District Attorney Harvey Dent (originally named Kent) as the key piece of evidence when Maroni was tried for Benson’s murder.
After Maroni scarred Dent with acid, the D.A. kept the coin for himself, scratching one side with a blade as a reflecting of his own “two faces.” On the brink of insanity and the precipice of either resigning himself to his situation or turning over to a life of crime, Dent flipped the coin, which landed scratched side up. Taking this as an omen that “evil wins!” Dent vowed to dedicate his life to the coin’s edicts, and thus Two-Face was born.
If the coin came up scratched, Two-Face would commit crimes like bank robbery and murder. If the coin came up clean, he would donate his ill-gotten money to charity. His dependence on the coin became so great that when it once landed on edge in a floor crack, Two-Face was immobilized and unable to decide for himself.
Just as Two-Face was about to let himself be turned in, a panicked police officer shot him in the chest, the bullet lodging in the scarred side of the coin, which was in Two-Face's coat pocket. This proved to the villain further proof that fate was driving him to be evil. Eventually, Dent returned to sanity, leaving the coin to Batman, who placed it in the Batcave’s trophy room.
During Dent’s temporary rehabilitation, several impostors took up the mantle of Two-Face, including Dent’s butler, actor George Blake, and--most notably--Paul Sloane, who was hired to play Dent in a TV biopic.
Many years later, Maroni returned and shot at Dent, but the bullet ricocheted off the coin in mid-flip and into Maroni, seemingly killing the mobster (it was later revealed that Maroni survived, but was crippled from the waist down for life). Once again, Dent took this as a sign from fate that Maroni was destined to die, and since the coin landed clean side up, Dent was therefore destined to peacefully return to Arkham Asylum.
In current continuity, the two-headed coin is one of many which belonged to Harvey’s father, Christopher Dent, an alcoholic who would use the coin to psychologically and physically abuse Harvey.
Whenever Harvey was a “bad boy,” the elder Dent would regularly subject his son to a cruel “game,” forcing the boy to play tails on
the coin flip to decide. Subsequently, Harvey would always lose the “game,” and would then get savagely beaten by his father. While one side of Harvey deep down knew the game was rigged, the other side refused to let himself consciously believe that his own father would do such a thing.
After years of estrangement, Harvey wanted to make peace with his father and paid the old man a visit. The perpetually-drunken Christopher Dent, now a derelict living in a run-down apartment, was grateful to see his son, and seemed to have no memory of the “game” or his abuse. As a sign of love, he decided to give Harvey the coin as a gift, not realizing the impact this would have on his son. Harvey now had definitive proof that the coin was two-headed, the game was rigged, and that he never had any choice.
This kicked off a chain of events that led to Dent's psychological unraveling,climaxing at the trial of “Boss” Maroni. The gangster’s acid not only scarred Dent’s face, but also one side of the coin, which was in his pocket. Seeing that the coin now had two faces like himself, Dent’s two warring sides split apart entirely, and were deadlocked in eternal opposition. As the coin was now fair, he used it as the tie-breaker between his two sides, acting for either his nobler instincts or his darker impulses depending on how it lands.
Dent went by the name "Two-Face" and took the coin on a rampage and killed his duplicitous former assistant Vernon Wells. After losing the coin in the attack, he returned to his father to get a new one, knowing that the old man had “plenty more.” He then manually scarred this new coin. Finally confronting his father, he played the “game” with the new coin, and good heads came up, so Two-Face let the old man live.
As Two-Face, Dent is rarely seen without his coin, although whether the coin he uses at any given time is the same one his father used, the new one he took, or another coin altogether is never explained. Batman has also been known to keep one of the scarred coins in his trophy room, one of which was nearly stolen by thieves who broke into the Batcave (Batman #577).
No matter which coin Two-Face is using at any point, he guards it fastidiously and almost always refuses to give it up. One exception came at the start of No Man's Land, where Renee Montoya earns his trust enough to let her hold onto the coin while they helped earthquake survivors. After they parted ways, Dent let her keep the coin, which she then used to give her depressed brother a harsh but loving lesson on how free will is a burden, but without it, you're no better than Two-Face.
Even though the coin Dent usually uses is a fake dollar, it’s genuinely silver, as evidenced by one occasion when Two-Face used the coin to kill a werewolf. Most recently, the coin has been ruined in a firefight with Mario Falcone, and then stolen by Gilda Dent, who has used it to lure a deranged and desperate Two-Face back to her.
The coin is given no explanation in the actual television show, Batman: The Animated Series, but in one of the TAS tie-in comics, it is revealed as having been owned by Harvey’s abusive father, a gambling addict and used-car salesman named Lester Dent.
Unlike Christopher Dent from the regular DCU, Lester Dent actually played fair with his “game,” never laying a finger on little Harvey whenever the coin came clean side up. How Lester’s “lucky” coin got scarred in the first place is never explained. Lester did this, he later feebly explained, to teach Harvey that everyone in life is at the mercy of chance.
Live Action Films
In Batman Forever, the coin was adorned with the image of "Lady Gotham," the Statue of Liberty analogue that stood in Gotham Harbor. A replica of this coin was released with the Two-Face action figure, as well as an officially-licensed prop from DC Direct.
In The Dark Knight, Dent left his coin with Rachel and in the explosion that kills her, the coin was burnt on one side, while fine on the other. This would add to Dent's insanity to become Two-Face.
The coin is often depicted as a 1922 silver Peace Dollar as was the case in his third Golden Age appearance (the finale of the original Harvey Kent trilogy) and in The Dark Knight, although the date has sometimes been written 1932. Other times, the coin is drawn as a Washington quarter or a Kennedy half-dollar. Recently, the coin has been golden rather than silver, perhaps indicating that Two-Face is now using a Sacagawea dollar coin.