The central character of the novel, Julien is the nineteen-year-old son of a provincial carpenter. Ambitious, intelligent, fierce, hypocritical, and an admirer of Napoleon, Julien dreams of rising in the ranks of French society. His photographic memory gives him the opportunity to become a successful priest, but Julien wants only to be a soldier. He tries to balance the two career impulses by becoming a tutor and seducing women. Like any romantic hero, Julien falls in love with his conquests, but also never really has any idea what he is doing. What he knows of the real world comes from books, never experience. He is obsessed with becoming a modern day Napoleon, but always lets those around him choose his own path. Blind ambition leads him to forego less "glorious" opportunities and true love. His failure to succeed in both love and life is also the failure of a society that has no place for him.
Both an aristocrat and the wife of the town mayor, Mme. de Rênal is Julien's first love interest. Mme. de Rênal truly loves Julien and although she cheats on her husband, she is a symbol of moral purity and kindness. Unlike every other character, Mme. de Rênal is honest, compassionate, and resourceful. She is one of the few characters in all of French literature to die of love.
The daughter of the Marquis, Mathilde is bored with Parisian society and immediately takes a liking to Julien. Slightly imbalanced, Mathilde has a flair for the dramatic. She is obsessed with her ancestor Boniface de la Mole and pretends that Julien looks and acts like him. She falls in love with Julien and urges her father to ennoble him because she cannot forget Julien's lower class status.
Although not a physical character in the novel, Napoleon's rise to fame and military glory are a constant model for Julien. Julien dreams of rising to the top of French society and uses Napoleon's military techniques to seduce women.
The mayor of Verrières. M. de Rênal is a conservative supporter of the Restoration and as a result, is conceited, obtuse, and greedy. He is concerned only with his title and rank, even though he is constantly manipulated and ridiculed. Julien sees him as an adversary.
The benefactor of M. Pirard and Julien's employer in Paris. Marquis de la Mole is a symbol of the dying aristocracy. He treats Julien as an equal, but only when Julien wears the right clothes. He is fearful of Julien's intelligence and ambition and ennobles him reluctantly.
The priest of Verrières, M. Chélan recognizes Julien's intelligence and stunning memory, but also sees Julien's lack of devotion to the Church. Kind-hearted and benevolent, he chooses to be Julien's mentor and teach him Latin anyway.
The director of the seminary and Julien's protector. M. Pirard shuns politics but the Church has become so corrupt that he resigns. He is a powerful figure in Julien's life, first promoting him in the seminary and then introducing him to the Marquis.
A bourgeois liberal and thus M. de Rênal's nemesis. M. Valenod has made his fortune by running the local poorhouse, cheating the less fortunate of society out of what little money they have. He is jealous of Julien's affair with Mme. de Rênal and avenges his pride by voting for Julien's execution. The novel's most corrupt character, he is also its most successful in society.
A member of the Marquis's salon. She is very religious, so Julien uses her attention to make Mathilde jealous.
Mme. de Rênal's maid. Elisa is the first woman to fall in love with Julien and is so jealous of his affair with Mme. de Rênal that she tells M. Valenod about it.
Julien's only friend. He lives in the mountains above Verrières and works in the lumber business. He offers Julien a job that promises wealth but little glory.