Buck lives living a charmed life on the estate of Judge Miller, during the time of the Klondike Gold Rush in 1897. He is the king of all the animals on the estate and as such enjoys special privileges, such as the run of the estate and the admirable position of being the Judge's favorite dog. However, Manuel steals Buck and sells him to the Klondike after he decided to pay off his gambling addiction with Chinese lottery for his family. He is shipped to Seattle. Put in a crate, he is starved and ill-treated by The Baggage Man. When released, he attacks his overseer, known only as the Man in the Red Sweater but is badly beaten and taught to respect the "law of the club". Buck is then sold to a pair of French-Canadian mailers named François and Perrault, who take him to the Klondike region of Alaska, where he meets other sled dogs, including Spitz. Buck defeats Spitz and is eventually sold to a kind man named John Thornton after he buys him from Hal, Mercedes and Charles. When Buck hears the howls of wolves coming from the forest, he answers the call and becomes a legend in the Klondike after Thornton was killed by the Yeehats.
- He was a gardener in the book, but in the 1972 film, he was a housekeeper.
- In the 1972 film, Judge Miller had another assistant named Jack.
- In the 1976 film, Manuel claimed that he would be fired by Judge Miller for stealing Buck.
- In the 1997 film Call of the Wild: Dog of the Yukon, Manuel is credited as "The Kidnapper" and his face was not shown.
- He didn't exist in the 2020 adaptation. Instead, he is replaced by an unnamed stranger.
- In Disney's White Fang, Buck made two cameo appearances where he is sold to Alaska and bought by Beauty Smith to become a fighting dog.