Judge Miller is rich, and he respects other people. He likes hunting, fishing, and swimming. He is Buck's owner. He has dignity,and a big house which is in the sun- kissed Santa Clara Valley. It stood back from the road, half hidden among the trees. It has a wide cool verandah that runs around the four sides. Buck is treated like a member of his family. "He was neither house-dog nor kennel-dog the whole realm was his. He plunged into the swimming tank, or went hunting with the judge's sons, he escorted Mollie and Alice, the judge's daughters on long twilight or early mornings rambles. On wintry nights he lay at the judge's feet before the roaring libary fire. He carried the judge's grandsons on his back, or rolled with them in the grass, and guarded there footsteps where ever they went. All through wild adventures down to the fountain, in the stable yard, and even beyond where the paddoks where, and the berry patches."
Manuel is a garden's helper. He loves to play the chinese lottery and loves gambling. He dognaps Buck because he needs lots of money to play chinese lottery and to feed his big family. The man who buys Buck from Manuel is a stranger. The stranger puts a rope around his neck, but Buck bites the stranger. The stranger puts Buck into a cage and onto a train. For two whole days Buck goes without food or water.
In Seattle Buck meets the man in the red sweater. He is a dog tamer. He beats Buck to teach him a lesson.
Perrault buys Buck from the man in the red sweater. He is a french canadian. He works with the canadian government. Perrault knew dogs and when he looked at Buck he knew that he was one in the thousand, one in ten thosand, he commented mentally.
Francois is Perrault's partner. He was a french canadian half- breed and twice as swarthy. Perrault and Francois were a new kind of men to Buck "of which he was dertined to see many more and while he developed no affection for them, he none the less grew honestly to respect them". They were both fair men.
Perrault and Francois tool him by boat to Dyea. On the boat, Buck meets three other dogs, they are Curly, Spitz, and Dave. Spitz was a big, snow white fellow from Spitzbergen. He had travelled all over the world with his owners, and he was a leader. Dave made no advances, he was a glommy, morose fellow, he showed Curly he only wanted to be left alone. Curly is kind and friendly. She got killed as soon as she arrived in Dyea.
After Curly is killed Buck starts to hate Spitz because he sees that he was laughing when she died. From then onwards Buck made Spitz's life as difficult as possible.
Spitz hates Buck because Buck is making his life difficult, and he is strong and needs to show the others who is team leader, but Buck is turning the rest of the team against him.
Perrault and francois acquire some more dogs. One of them is called Sol-leks. He has only one eye. Sol-leks means the angry one. Billy and Joe are brothers, they are two dogs who are very different from each other. They were both true huskies. Billy's one fault was his excessive good nature, while Joe was the very opposite, sour and introspective with a malignant eye. Buck recived them in comradely fashion. Dave is a very experienced dog, but he is the first in the team to die because he had some bad illness what the rest of the team didn't know. They said that he would die in the traces, heart-easy and content. Several times he fell down and was dragged into the traces, but he held out till camp was reached. Then he tried to crawl to his driver. He would advance his forelegs and drag up his body with a sort of hitching movement. In the end his driver shot him out of mercy.
Buck does not get as close to the scotch-half breed because he takes a lot of time day dreaming against the fire after he has eaten all his dinner. There are 100 dogs and lots and lots of drivers. It is far more organised.
Hal and Charles are travelling with Hal's sister, the wife of Charles. Her name is Mercedes. At the start of the journey we learn that they don't know how to drive the dogs or themselves. They are un experienced and new to it all. During the journey we learn that they become more and more hungry because they have undersetimated the amount of dog food they will need. They are tired because they have to walk far and they had no rest.
John Thornton who rescues Buck is a completely different character. He rapped Hal's knuckles with the axe handle, knocking the knife to the ground, when Hal threatened him. He is kind and friendly to Buck. Buck romped through his convalescence and into a new existence. This he had never experienced at Judge Miller's down in the sun-kissed Santa Clara Valley. John Thornton had saved Buck's life and was his ideal master. He had a way of taking Buck's head roughly between his hands and he resting his own head upon Buck's.
As the story progresses, Buck changes from a soft, kind friendly dog. He changes into a stronger dog. He becomes better at walking long distances. He does goes hunting for their living meat.
Buck is most influenced by John Thornton because he saved Buck's life, took him hunting and he learnt Buck how to defy all of the bravest hunters.