Jody is the ten-year-old son of Carl and Ruth Tiflin, living on a ranch in the Salinas Valley. He possesses a vivid imagination but strongly resists personal responsibility. He frequently acts out violently toward the farm animals when bored or frustrated. Receiving a red pony from his father forces him to face the hard realities of caring for another living creature.

Billy is a middle-aged ranch hand employed by Carl Tiflin. He holds a reputation as a highly skilled horse expert and feels personally responsible for the animals on the property. As the son of a government mule packer, he respects the history of westward expansion and maintains a practical connection with the natural world around him.

Carl manages his family's ranch in the Salinas Valley with a strict and unsentimental approach. He measures the worth of people and animals purely by their physical usefulness and daily productivity. This mindset causes tension with the more empathetic residents of his household when he openly criticizes sickness and advanced age.

Ruth manages the domestic sphere of the Tiflin ranch. She serves as a buffer between her husband's harshness and the rest of the household. While generally quiet, she carries weight in her marriage and forcefully defends her aging father when her temper rises.

Ruth's father is an elderly man defined entirely by his past as a leader of a wagon train during the westward expansion. He possesses a dignified bearing but feels lost in a modern world where the frontier has vanished at the edge of the Pacific Ocean. He relies on retelling stories to maintain his sense of purpose and identity.

Gitano is an elderly paisano man who returns to the Tiflin ranch because he was born in an old adobe house on the property. He carries his belongings in a small bag, bringing a quiet mystery that fascinates the younger residents. He seeks only a peaceful place to live out his final days on the land of his birth.

Gabilan is a young red pony colt brought to the ranch as a gift to teach Jody responsibility. Named after the eastern mountains of the Salinas Valley, the pony is initially spirited, prone to biting, and resistant to halter-breaking before settling into training.

Doubletree Mutt is one of the two working dogs on the Tiflin property. He is a loyal farm animal who frequently suffers the brunt of Jody's idle cruelty and violent outbursts.

Smasher is a shepherd dog serving the Tiflin ranch. He acts as a companion to the other animals and a general guardian of the property.

Easter is a thirty-year-old horse on the Tiflin ranch who has outlived her physical usefulness. While the ranch hand believes she has earned her retirement, the ranch owner views her as a waste of resources.

Nellie is a working mare on the Tiflin ranch. She is chosen to be bred with a neighbor's stallion to provide a new colt, becoming the center of renewed hopes and promises on the farm.

Jess Taylor is a neighboring rancher in the Salinas Valley. He maintains a friendly business relationship with the Tiflins and owns the local breeding stallion.

Sundog is a powerful stallion belonging to a neighboring rancher. He is known to be aggressive and dangerous, inspiring awe in the younger visitors to the property.