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. |