Mr. Biswas is born unlucky. This lack of luck follows him from birth and even leads to the death of his father. However, he does not let this stop him. He is in many ways like the Biblical character of Job, for whom all that can go wrong does go wrong. He is in a mostly unhappy marriage to a woman that he did not know prior to marrying, but over time he finds joy in the accomplishments of his two eldest children. His lifelong goal is to purchase a house of his own, which is rare on the small, mostly impoverished island of Trinidad. Though he loses sight of this goal at times and faces many setbacks, he does eventually purchase a house and become head of his own household.
Shama, an attractive young woman, marries Mr. Biswas when she is only sixteen. Their marriage is a troubled one from the beginning, as Mr. Biswas has little to offer her. Over time, she matures and even at times shows pride in her husband's journalistic accomplishments. The marriage between Shama and Mr. Biswas, quite shaky at first, becomes more stable, though not necessarily happy, as the couple ages.
Savi changes greatly over the course of the novel. There is a struggle between Mr. Biswas and Shama for control of her, even from birth. It seems as though Shama and the Tulsis, who name her, will retain control over her upbringing. She spends much of her childhood at Hanuman House and is heavily influenced by her aunts, uncles, and cousins in her youth. However, as she grows up, she realizes the accomplishments of her father and becomes a full-fledged member of the Biswas family, even spending significant time with her father in his final days.
Unlike Savi, Anand seems to have a deep love for and understanding of his father right from the start. Though the two quarrel and Mr. Biswas even beats him, Anand sticks by him during his darkest times. He is the first member of the Biswas family to show academic promise, and he wins a college scholarship. Sadly, Anand is unable to return home to see his father prior to his death, which suggests in some ways that even though his opportunities are the result of his father's insistence on his education, he now has a life of his own that does not include his parents and siblings.
Mrs. Tulsi begins as a very strong figure, controlling much of what happens at Hanuman House, the Tulsi Store, and all the Tulsi properties with her brother-in-law Seth. She is very indulgent toward her sons, whom Mr. Biswas believes are treated like gods. As the widow of a great pundit, she is also very serious about her practice of Hinduism, though sometimes she incorporates Christian elements into her rituals. As the novel progresses, she ages and becomes less and less of a daily force, though her word is still followed by all.
Like Mr. Biswas, Seth married into the Tulsi family. However, at the death of Mrs. Tulsi's husband, he seized the opportunity to take control of the Tulsi family. He is a wealthy planter who owns many properties. It is Seth who makes many of the decisions about where Mr. Biswas and Shama are to live after they are first married. Toward the end of the novel, a rift forms between he and the Tulsis, and Owad takes over as head of the family.