Sydney Carton proves the most dynamic character in A Tale of Two Cities. He first appears as a lazy, alcoholic attorney who cannot muster even the smallest amount of interest in his own life. He describes his existence as a supreme waste of life and takes every opportunity to declare that he cares for nothing and no one. But the reader senses, even in the initial chapters of the novel, that Carton in fact feels something that he perhaps cannot articulate. In his conversation with the recently acquitted Charles Darnay, Carton's comments about Lucie Manette, while bitter and sardonic, betray his interest in, and budding feelings for, the gentle girl. Eventually, Carton reaches a point where he can admit his feelings to Lucie herself. Before Lucie weds Darnay, Carton professes his love to her, though he still persists in seeing himself as essentially worthless. This scene marks a vital transition for Carton and lays the foundation for the supreme sacrifice that he makes at the novel's end.

Carton's death has provided much material for scholars and critics of Dickens's novel. Some readers consider it the inevitable conclusion to a work obsessed with the themes of redemption and resurrection. According to this interpretation, Carton becomes a Christ-like figure, a selfless martyr whose death enables the happiness of his beloved and ensures his own immortality. Other readers, however, question the ultimate significance of Carton's final act. They argue that since Carton initially places little value on his existence, the sacrifice of his life proves relatively easy. However, Dickens's frequent use in his text of other resurrection imagery—his motifs of wine and blood, for example—suggests that he did intend for Carton's death to be redemptive, whether or not it ultimately appears so to the reader. As Carton goes to the guillotine, the narrator tells us that he envisions a beautiful, idyllic Paris “rising from the abyss” and sees “the evil of this time and of the previous time of which this is the natural birth, gradually making expiation for itself and wearing out.” Just as the apocalyptic violence of the revolution precedes a new society's birth, perhaps it is only in the sacrifice of his life that Carton can establish his life's great worth.