| 1 | Buck | | Judge Miller's dog. |
| | | | Judge Miller's Place - House of Buck. |
| | Toots | | The Japanese Pug. |
| | Ysabel | | The Mexican Hairless. |
| | Judge | Miller | Buck's first owner. |
| | Mollie | Miller | Daughter of Judge Miller. |
| | Alice | Miller | Daughter of Judge Miller. |
| | Elmo | | St. Bernard / Father of Buck. |
| | Manuel | | The gardener's helper who kidnapped Buck. |
| | Saloon-Keeper | | The man who tormented Buck. |
| | Perrault | | French-Canadian man trains sled dogs. Friend of Francois. |
| | Curly | | Friend of Buck. |
| | Francois | | French-Canadian mail driver bought Buck.
Perrault's friend. |
| | Dave | | The new sled dog of Francois / A lazy dog. |
| 2 | Spitz | | The leader of Francois's dog-team / A big snow-dog. |
| | Bilee | | New sled dog of Francois / A Husky. |
| | Joe | | New sled dog of Francois / A Husky. |
| | Sol-leks | | An old husky / Francois new sled dog. |
| | Pike | | New sled dog of Francois / A clever malingerer and thief. |
| | Dub | | An awkward blunderer. |
| 3 | Dolly | | The last dog added to Francois's "sled dog team". |
| 4 | Teek | | A native husky. |
| | Koona | | A native husky. |
| 5 | Hal | | American gold seeker.
Bought buck from Francois & Perrault. |
| | Charles | | Brother-in-law of Hal / Mercedes's husband. |
| | Mercedes | | Sister of Hal / Charles's wife. |
| | John | Thornton | Buck's new owner / The man who saved Buck's life. |
| 6 | Hans | | John Thornton's partner. |
| | Pete | | John Thornton's partner. |
| | Matthewson | | A Bonanza king. |
| | Jim O'Brien | | A Mastodon king. |
