Alfred Archibald Jones
Archie, the protagonist, is mediocre and indecisive, preferring to make his most important decisions with the flip of a coin. Archie's ex-wife is Ophelia Diagilo, whom he supposedly drove insane with his mediocrity. He later marries Clara, a Jamaican woman less than half his age, with whom he has a daughter, Irie. Archie's best friend is Samad Iqbal. The two men served together in World War II in the British Army and frequently visit O'Connell's pub.
Samad Miah Iqbal
Archie's best friend, a middle-aged World War II veteran with a crippled right hand. Samad was born in Bangladesh and met Archie when they were soldiers in Eastern Europe. He works as a waiter at an Indian restaurant, where he receives few tips. His wife is Alsana Begum, and his twin sons are Magid and Millat. More than anything, Samad wants his sons to grow into religious, traditional Bengali Muslim men. To ensure this, he goes to great lengths, even sending Magid to be raised in Bangladesh (for all intents and purposes, this was a kidnapping). Samad is religious and outspoken, relishes control although he is a staunch believer in destiny, and fancies himself to be more worldly and intellectual than others credit him. Samad's plot revolves around the difficulties he finds adapting to British culture while still holding on to his Bangladeshi heritage, and also raising his second-generation immigrant sons while they become a product of cross-cultural identity.
Clara Jones, née Bowden, was an awkward, unpopular Jehovah's Witness who spent her adolescence proselytizing door-to-door. When she meets the equally unappealing Ryan Topps, she abandons her religion and takes up his rebellious ways, though Ryan becomes a staunch Jehovah's Witness himself. When Ryan and Clara crash into a tree on Ryan's scooter, Clara's top teeth are knocked out. She meets Archie Jones and marries him, even though she finds him unimpressive and he is more than twice her age. Archie and Clara have a daughter named Irie.
Alsana Iqbal, née Begum, is the young wife of Samad Iqbal, to whom she was promised before her birth. They have twin sons, Magid and Millat. To help pay bills, she sews clothing for an S&M shop called Domination in Soho. Although charismatic and judgmental by nature, she thinks marriage is best handled with silence. However, she has a volcanic temper and generally wins fights with Samad by injuring him.
Irie Ambrosia Jones
Irie – whose name means "OK, cool, peaceful" in Patois – is the daughter of Clara and Archie Jones. Irie has been friends with Magid and Millat Iqbal since birth. After struggling with her racial and sexual identity, Irie finds answers in her grandmother, Hortense Bowden. She resolves to go into the field of dentistry and, despite her best efforts to prevent it, ends up with Joshua Chalfen. Having slept with both Magid and Millat, Irie gives birth to a daughter whose father can never be known, as the twins have exactly the same DNA.
Millat Zulfikar Iqbal
Millat is the younger son of Samad and Alsana, and twin brother of Magid. After Magid is sent to Bangladesh, Millat comes into his own as a trouble-making, pot-smoking rebel who engages in a large amount of sexual activity. However, Millat eventually rejects this lifestyle in favor of fundamentalist Islam, becoming a major driving force of KEVIN. At the FutureMouse conference, he tries to shoot Dr Perret, but instead shoots Archie in the thigh. Millat may or may not be the father of Irie's baby.
Magid Mahfooz Murshed Mubtasim Iqbal
Magid is the elder son of Samad and Alsana, and twin brother of Millat. Magid is intellectually precocious and insists on dressing and acting like an adult, even at a very young age. Magid resents his heritage and wishes he and his family were more "normal" and English. Samad essentially kidnaps Magid and sends him to be raised traditionally in Bangladesh. To his father's unhappiness, Magid becomes a suit-wearing, secular, English intellectual. When he finally returns to London, he joins Marcus Chalfen's FutureMouse program. Magid is fascinated by the certainty of fate genetic engineering offers, and by having the power to choose another creature's path, as his was chosen for him. Magid may or may not be the father of Irie's baby.
Marcus Chalfen is a Jewish genetic engineer and husband of Joyce Chalfen. His controversial FutureMouse experiment involves genetically altering a mouse so that it develops cancers at specific times and sites. Marcus loses interest in mentoring Irie when he begins corresponding with Magid.
Joyce is a horticulturalist, writer, and the wife of Marcus Chalfen. She has four sons, all who adore her fiercely. Joyce is a natural nurturer and constantly feels the need to care for things and people. From the moment they meet, Millat entrances Joyce, and she feels the need to mother him and pander to his needs.
Joshua is the son of Joyce and Marcus Chalfen. Originally interested in his studies at Glenard Oak School, Joshua rebels against the Chalfens (particularly his father) by joining the animal-rights groups FATE. Joshua has a long-standing crush on Irie and, later, on Joely. He stays in FATE largely as an excuse to remain close to her.