Munoo is a 14-year-old orphan from the hill country of north-central India who enters the adult working class out of financial necessity. Lacking formal education and specific skills, he searches for gainful employment to survive. He works as a domestic servant, a factory worker, and a rickshaw puller across various cities. Despite his grueling circumstances and frequent displacement, he retains an eager optimism, an appreciation for the beauty of nature, and a fierce instinct to survive.

Ratan is a burly former wrestler who works as a coolie in the Bombay cotton mill. Standing out from the exhausted crowds of laborers, he possesses an enormous appetite for life and refuses to accept the oppressive conditions of the caste system. He acts as a moral compass for his fellow workers, openly agitating for fair treatment, better conditions, and the right to form a union.

May Mainwaring is a wealthy Anglo-Indian woman who actively cultivates the persona of a refined British aristocrat to obscure her biracial heritage. Anxious about her social standing, she spends time networking with expatriates and arranging a new household in the mountain town of Simla. She brings Munoo into her home, displaying a highly solicitous attitude mixed with a disturbing level of infatuation for her new servant.

Babu Nathoo Ram is a sub-accountant at a bank in Sham Nagar who takes Munoo in as a domestic servant. He views his position as a middle-class clerk as a stepping stone and tries desperately to impress his British superiors. While he occasionally attempts to instruct Munoo with a degree of patience, his actions are dictated by his desire for social advancement rather than genuine compassion.

Bibiji is the wife of Babu Nathoo Ram and the primary manager of their home in Sham Nagar. She enforces rigid domestic rules and views the working class as fundamentally inferior. She frequently berates Munoo for minor mistakes, denying him adequate food or basic respect while demanding constant labor in her kitchen.

Sheila is the eldest daughter of Babu Nathoo Ram and Bibiji. Four years younger than Munoo, she approaches the new servant without the ingrained prejudices of her parents, treating him more like a playmate. Their interactions reveal the temporary, fragile nature of childhood innocence before societal rules enforce strict divisions.

Prabha Dyal is the gentle-hearted co-owner of a sprawling chutney factory in the town of Daulatpur. After finding Munoo on a train, he and his wife invite the boy into their spacious home and offer him employment. He runs his business with a trusting nature, relying heavily on his partner while ignoring the corruption required to keep the factory operating.

The wife of Prabha Dyal is a frail but loving woman recovering from the emotional devastation of a miscarriage. She sees Munoo not as a nameless coolie but as a surrogate son, eagerly welcoming him into her home. She provides Munoo with a rare experience of maternal care and emotional stability.

Ganpat is Prabha Dyal's business partner and the son of wealthy parents. He oversees the daily operations of the chutney factory, where he routinely curses, berates, and beats the coolies to force higher production rates. Viewing the workers with contempt, he secretly manipulates the company's finances for his personal amusement and gain.

Guy Mainwaring is a young British Air Force officer who married May following her divorce. Stationed primarily with his division in England, he remains geographically distant from his wife's daily life and social maneuvering in India, serving mainly as a symbol of the British legitimacy she desperately seeks.

Jimmie Thomas is the imposing foreman at the Bombay cotton factory. He strictly enforces production quotas and views the uneducated workforce as replaceable commodities. He demands commission fees from laborers seeking employment and uses constant verbal abuse and intimidation to keep the factory floor under absolute control.

Hari is a desperate coolie struggling to support his family in the crowded slums of Bombay. He guides Munoo through the intimidating process of finding work at the cotton mill and allows the boy to share his cramped company housing. He represents the trapped, fatalistic reality of adult workers who endure systemic abuse to avoid starvation.

Hari's wife manages the daily survival of her family within a squalid, smoke-filled hut provided by the factory. She offers Munoo a brief moment of maternal soothing after a confusing night in the city, providing comfort while instilling the harsh lesson that suffering is the inescapable destiny of their social class.

W. P. England is the British-born chief cashier at the bank where Nathoo Ram works. He represents the aloof, occupying British class, displaying profound discomfort and cultural disdain when hosted by his Indian subordinate. He rejects local customs and food, highlighting the immense social divide.

Sir Todar Mal is a powerful local government official living adjacent to the Daulatpur chutney plant. He frequently files complaints regarding the factory's heavy smoke and stench. Instead of demanding actual environmental improvements, he readily accepts regular bribes of factory goods in exchange for ignoring the health code violations.