- Creighton Brown: A British boy who is 15 gets in trouble with the law and who hates the British king. Hoping to cure him of his bad behavior, Creighton's mother sends him to the Colonies to live with his uncle. He is captured with Uncle Gower and Hale during the trip to the Colonies, but is released when he poses as an indentured servant. Creighton is then ordered to spy on his captors by Gower. He later gives himself up to Franklin by telling him his role in the escape of Col. Gower and Lt. Hale. He becomes Franklin's assistant in the print shop alongside Sophie, Franklin's French assistant. In the beginning of the book, Creighton is an arrogant Englishman who thought his only purpose in life was to play card games. In his adventures in the Colonies, he becomes aware of the many things in life besides games and ale. He faces challenges to figure out where his loyalties should lie.
- Benjamin Franklin: American Patriot who publishes The Liberty Tree, an underground rebel newspaper. Franklin takes Creighton in because he believes him to be loyal to the Patriots. He dies after a fire in the print shop started by British soldiers dressed as Native Americans.
- Benedict Arnold: American general who befriends Creighton. Arnold is a fighting man who favors violence over peaceful resolutions. He has a very bad temper and enjoys dueling. His leg was amputated in a battle.[3]
- Peter: A giant who is in the rebel army and is a year older than Creighton. Because of his size, he is sometimes clumsy. Peter's character is based on Peter Francisco, a private in the American army during the Revolution who was sixteen and stood six and a third feet tall. He is Creighton's first true giant friend, aside from Lieutenant Hale.
- Sophie: A French housemaid, 14 or 15 years of age, works for Franklin. Sophie's family was killed by British soldiers, so she despises most British people. Throughout the book, Sophie works on Franklin's 13 virtues, where she focuses on one per week. She struggles the most with humility. She and Creighton have a seemingly flirty relationship but do not openly show affection to one another. She also works in Franklin's print shop, helping him print the underground newspaper.
- Colonel Gower: He is Creighton's Uncle. Gower is a cruel and a disagreeable man who is made the Lieutenant Governor of West Florida. He invades French Haiti and succeeds in capturing it. He also supervises the execution of George Washington at the end of the story. He abandons Creighton with Franklin and Sophie.
- Lieutenant Harvey Hale: A British Royal Marine officer who is instructed to escort Creighton to America. The two become friends. Hale is imprisoned with Gower. They eventually escape and Hale becomes Gower's assistant.
- Harry Brown: Creighton's father who is jailed for warning American colonists about a forthcoming British-ordered Native American assault, but Creighton, along with Peter and Hale, rescue him.
- General George Washington: The American General in the Revolutionary War, who later is hanged.
The whole book is a historical fiction.
