Omri is the youngest of three brothers in a British family. He has a fondness for putting things in cupboards, which leads to his discovery of the magic cabinet. Striving to manage the massive responsibility of caring for a living, tiny human, he displays growing maturity and a strong moral compass.

Little Bear is a proud Iroquois warrior and chief's son from the 18th century, transported into Omri's modern world. Despite being the size of a toy, he expects respect and behaves with the dignity of a leader. He is fiercely brave, quick to adapt to his strange new surroundings, and possesses a strong sense of tradition.

Patrick is Omri's closest friend, sharing his interest in plastic toys and skateboards. When he learns of the magic cupboard, his excitement overpowers his judgment, viewing the living people merely as animated action figures. His selfish ambition to play with the tiny men creates severe risks for everyone involved.

Boone is a cowboy from 1889 who acts tough but has an overly sensitive, easily emotional nature, earning him the nickname "Boohoo" back home. He carries deep-seated biases against Indigenous Americans, preferring to drink and complain. Despite his gruff exterior, he possesses a remarkable talent for drawing.

Tommy is a cheerful, brave British medical soldier pulled from the trenches of World War I. Believing his experience to be a bizarre dream, he maintains his military composure and competence while treating injuries much smaller than he is accustomed to.

Bright Stars is a young Iroquois woman brought to life from a plastic figurine chosen at the local shop. She is capable, perceptive, and understands her native language, making her an ideal companion for a chief.

Mr. Johnson is the strict, cranky headmaster at Omri and Patrick's school. He is highly effective at interrogating misbehaving students and serves as a major threat to the boys' secret when their erratic behavior draws his suspicion.

Gillon is Omri's middle brother. He currently lacks an allowance due to a mishap with his father's bicycle, so he scavenges an alleyway find for a birthday gift. His loose pet rat creates a severe hazard in the household.

Adiel is Omri's oldest brother. He plays football and acts as a typical older sibling, sometimes picking fights or taking things as punishment. He inadvertently causes a major crisis when he confiscates Omri's belongings over a misunderstanding.

Mr. Yapp is the proprietor of the local news agent and toyshop where the boys frequently purchase plastic figurines. He is vigilant about theft and deeply suspicious of the boys when they handle the tiny men in his store.

Omri's mother is a caring and busy parent who activates the magic by providing her grandmother's ornate key. She tries to keep track of her three sons and is unaware of the incredible events happening in Omri's bedroom.

Omri's father is a practical man who worries about his garden and the household's upkeep. He accidentally creates problems for the tiny men by pulling up floorboards to hunt for a loose pet rat.

A tiny, spirited horse brought to life from a plastic toy. Initially terrified by the giant world and Omri's handling, the animal is quickly calmed and tamed by Little Bear.