David Balfour is accused of being an accomplice in the Appin Murder, a real life murder. The characters of Alan Breck Stewart, Colin Roy Campbell, James Stewart, Cluny Macpherson, and Robin Oig Macgregor were real people.
- David Balfour: Honest 17-year-old who heads out on his own after his father dies. His mother had died earlier. David is unaware that he is heir to an estate, the House of Shaws. Although David is a Lowland Scot, he could be any boy anywhere embarking on a journey from youth to manhood.
- Ebenezer Balfour: David's devious uncle. Ebenezer cheated David's father out of the House of Shaws. He first tries to murder David. When that scheme fails, he arranges to have him kidnapped and sold into slavery.
- Alexander Balfour: David's father, dishinherited by his younger brother Ebenezer Balfour.
- Mr. Campbell: Kind minister of Essendean who helps David at the beginning of his journey.
At sea and in the Hebrides
- Elias Hoseason: Captain of the Covenant. He "buys" David from Ebenezer in hopes of selling him into slavery at a profit.
- Mr. Shuan: First officer under Captain Hoseason. When he drinks, he is extremely cruel.
- Mr. Riach: Second officer under Captain Hoseason.
- Ransome: Abused cabin boy whom Hoseason uses to help ensnare David in the kidnap scheme.
- Old Man and His Wife: Poor but generous residents of the Island of Mull who give David food, drink, and valuable information, then allow him to rest in their hut.
- Guide: Island of Mull resident who lodges David for five shillings and agrees to guide him to Torosay.
- Hector Maclean: Island of Mull resident who changes a guinea into shillings so that David can pay the guide.
- Duncan Mackiegh: Blind man who guides David through part of the Island of Mull. In spite of his blindness, he knows every rock and bush on the island. He is a dangerous man who carries a pistol and can shoot "by ear". However, David pretends to have a pistol, too, and thereby avoids trouble with him.
- Neil Roy Macrob: Friend of Alan's and skipper of a ferry that takes David from Torosay to mainland Scotland. Macrob gives David directions for how to assemble with Stewart.
- Island of Mull Innkeeper: Man who befriends David and lodges him at Torosay.
In the Highlands
Alan Breck Stewart: A daring and foolhardy Highlander who has gone into exile in France and wears a French uniform. He is tasked with collecting funds for the exiled Jacobite leadership from the clans previously in rebellion against the Hanoverian crown. He becomes friends with David and helps him survive when both are hunted by soldiers through the wilderness. Stewart is based on a real-life Jacobite rebel of the same name. "Breck" is a nickname referring to pockmarking on his face.
Colin Roy Campbell: Also known as the "Red Fox." Scotsman loyal to the Hanoverian crown. He acts as the king's agent in two Highland counties, Appin and Mamore. His job is to collect taxes and claim for the Crown Scottish lands forfeited by pro-Jacobite clans. He is shot dead while talking with David. Alan is accused as the murderer and David as his accomplice. Colin is based on a real-life Scotsman of the same name who was shot dead near Ballachulish. His case became known as the "Appin Murder."
James of the Glen (James Stewart): Highland chieftain who lost his lands to the Hanoverian crown. He is the head of the Stewart clan to which Alan belongs. James is based on a real-life Scotsman of the same name who was accused of being an accomplice and aiding and abetting the murder of Colin Campbell. He was tried at Inveraray, found guilty, and hanged near Ballachulish November 8, 1752.
Mrs. Stewart: Wife of James Stewart. She treats David kindly and says she will always remember him.
Cluny Macpherson: Another chieftain who lost his lands, chief of clan Vourich. As a Jacobite rebel, he is in exile from Hanoverian rule and lives in a hideout near Ben Alder.
Robin Oig: Son of Rob Roy MacGregor, a famous Highland outlaw.
Henderland: Evangelist who becomes friends with David in the Highlands and provides him valuable information about the region. He is moderate and reasonable in carrying out his mission.
Queensferry Innkeeper: Man who provides some information about Ebenezer Balfour's background.
Mr. Rankeillor: Lawyer who helps David settle legal matters with his uncle.