Benedict Arnold is an American general who betrayed his country during the American Revolution, attempting to surrender a fort to the British and then later joining the side of the British.
When Timmy Turner wishes The Founding Fathers into the future so he can interview them on TV for a history report, Benedict Arnold is able to trick John Hancock into signing "The Decloration of Surrenderpendence", causing the United States to lose a war and remain a British colony. This turns Dimmsdale in the future into a very British looking place. Luckily Timmy was able to get The Founding Fathers back to their time and prevent Benedict Arnold from tricking Hancock. Benedict and George then began fighting over who was the real Washington until Cosmo helped Timmy get an idea. Timmy then got a wooden coat rack out in front of them. George then gave into his temptation and chopped up the coat rack. This caused the other people to figure out that was Washington. Jefferson then exposed Benedict by taking off his wig and poking him in the back with his quill to make him spit the fake wooden teeth out. Most of the people were shocked that he was a traitor although George notes that he always knew that Benedict was a traitor. The authorities then took Benedict by the arm and took him away.
Benedict has black hair, but is able to trick John Hancock into thinking he is really George Washington simply by putting on a powdered wig and a set of wooden teeth.