Sydney Carton’s heroic sacrifice is the single central action of the book, giving meaning to a life he has come to loathe and allowing him to die with such dignity and purpose that he finally achieves the status of prophet and martyr, foreseeing the fates of the other characters as he goes peacefully to his death. Although Carton’s self-sacrifice is the most striking in the novel, the chief moral difference between the good and evil characters is the willingness of the former to sacrifice their own interests for others or for a greater good, contrasted with the extreme selfishness of the latter. Lucie Manette spends her life caring for others, principally her father, though she also shows deep concern for Carton. Charles Darnay risks his life to help Gabelle. Miss Pross is willing to do anything to help those she loves, including both Lucie, who deserves her devotion, and her brother Solomon, who certainly does not. Solomon Pross, also known as John Barsad, uses and preys on his sister in an entirely cynical manner, conduct that marks him out as one of the toxically selfish characters in the book. The worst of these are the Sainte Evrémonde brothers, who abuse everyone around them for their own pleasure and convenience. The Marquis de Sainte Evrémonde is so entirely self-absorbed that he shows not the slightest concern at killing a child when driving his carriage too fast.

Sydney Carton initially appears to have a thoroughly selfish, cynical outlook on life. He sullenly tells Charles Darnay: “I care for no man on earth, and no man on earth cares for me.” It is his sacrifice and heroism at the end of the novel that redeems him and aligns him with the selfless characters, as the most heroic of them all.