Charles is an aristocratic gentleman and amateur paleontologist visiting the coastal town of Lyme Regis. As the presumptive heir to his uncle's estate, he enjoys a life of leisure but feels a growing sense of alienation from traditional Victorian expectations. His fascination with the progressive theories of Charles Darwin reflects his restless intellect. He finds himself increasingly intrigued by the social outcast Sarah Woodruff, an interest that threatens his comfortable position in society.

Sarah is an educated woman from a farming family who previously worked as a governess. The local townspeople refer to her derisively as "Tragedy" or "The French Lieutenant's Woman" due to her melancholic behavior following a rumored romance with a shipwrecked sailor. She currently works as a companion to the severe Mrs. Poulteney. Her profound sense of isolation sets her apart from the polite society of Lyme Regis.

Ernestina is the only child of a wealthy London businessman. She is staying with her Aunt Tranter in Lyme Regis to recover from the social season. She strictly adheres to the rigid manners and polite expectations of Victorian society. Her traditional view of courtship contrasts heavily with Charles's modern leanings.

Operating from a 1960s perspective, this self-conscious authorial voice provides a modern lens on the Victorian setting. He occasionally interrupts the narrative to critique 19th-century social mores, discuss Karl Marx, and analyze the psychological constraints placed upon his characters. He openly struggles with the traditional conventions of literature.

Sam is Charles's young manservant of four years. He frequently spends his wages on fashionable clothing to shed his cockney background. Beneath his deference to his employer, he possesses a keen ambition to eventually leave domestic service and open a haberdashery of his own.

Mary is a lively and attractive young servant working in Aunt Tranter's household. She previously lost a position at Mrs. Poulteney's house due to a minor indiscretion. She envies Ernestina's fashionable clothes and finds amusement in teasing the higher-class guests.

Mrs. Poulteney is a wealthy, self-righteous woman who demands exceptionally high standards from her household staff. Driven by a deep-seated fear of hell rather than genuine compassion, she takes Sarah Woodruff into her home as a calculated good deed. She rigorously polices the morality of the local townspeople.

Aunt Tranter is Ernestina's relentlessly optimistic aunt who lives in Lyme Regis. Unlike the severe Mrs. Poulteney, she manages her household with kindness and maintains a warm, forgiving attitude toward her servants and guests.

Dr. Grogan is an Irish Catholic physician who has converted to Anglicanism and settled in Lyme Regis. Despite his respected medical position, his Irish heritage keeps him somewhat marginalized in polite English society. He shares Charles's progressive interest in science.

Mrs. Fairley is the head cook and housekeeper for Mrs. Poulteney. She shares her employer's harsh, critical tendencies and keeps a close watch on the other servants. She feels threatened by Sarah's arrival and actively spies on the younger woman.

Mr. Freeman is Ernestina's father and a highly successful businessman. He represents the newly wealthy, upwardly mobile middle class of the Victorian era. He harbors conservative religious views and expects his daughter to secure a socially advantageous marriage.

Sir Robert is an aging aristocrat who owns the sprawling Winsyatt estate. He frequently criticizes Charles for his lack of political ambition and his failure to settle down, though he himself has remained unmarried for many years.

The French Lieutenant is a foreign sailor who survived a shipwreck and recovered at the local Talbot household. He is the central figure in the town's gossip regarding Sarah Woodruff, having left a lasting, scandalous mark on her life before returning to France.