Nina Sayers/The Swan Queen
Nina is a dancer in a New York City ballet company which is preparing for Tchaikovsky's Swan Lake. She wins the prima ballerina role. She begins to have hallucinations in her preparation and is afraid that Lily will take her role as she is made Nina's replacement. The hallucinations continue into her performance where she performs flawlessly after having a fight in which she stabbed herself believing it to be a doppelganger. She is cheered with a standing ovation, but passes out after Thomas tells her she had a perfect performance.
Lily/The Black Swan
Lily is a member of the same New York ballet company as Nina. She is made Nina's alternate for the production of Swan Lake. Nina makes her out to be the villain in the story and we aren't sure if Lily is real or merely a hallucination to Nina.
Thomas Leroy
Thomas Leroy is the artistic director of the New York ballet company that is preparing to perform Tchaikovsky's Swan Lake. His greatest task is finding a replacement for prima ballerina, Beth who has been forced to retire. He is a hard-driving man who comes on to Nina in exchange for the lead role.
Erica Sayers/The Queen
Erica is Nina's mother. She is considerably controlling of her daughter. She lives vicariously through her daughter and at the same time seems to be jealous of her.
Elizabeth "Beth" MacIntyre/The Dying Swan
Beth was the prima ballerina of the New York ballet company that Nina is part of. She is forced to retire by Thomas due to their clashing and her age. It is revealed that Beth may have slept with Thomas to become prima ballerina and she believes Nina has done the same.