Natalie Portman
Although the main character in the movie, Nina Sayers is not the person who the movie is named after, as she is not the "Black Swan". Another character, named Lily, is. Nina Sayers is nicknamed the Swan Queen for her wonderful and beautiful performances as a ballerina, and she is the main character and protagonist of the film. As she is trying to stop the antagonist, Lily, and is the one driving many of the themes and ideas in the movie, she fits both of those roles.
Natalie Portman was born in 1981 and is a well-known and respected actress. Her first work in a film was in 1994, when she acted in Leon: The Professional. She has won a Golden Globe Award, has been nominated for an Academy Award, and has other smaller titles for her roles in other films. Black Swan is one of her better known works.
Mila Kunis
Mila Kunis acts out the part of Lily, who is the Black Swan that the film is named after. Lily is the antagonist of the film, and when Nina learns of her, she is upset. Nina is told that Lily has special qualities that make her good at dancing that she could never have, and Lily later invites Nina for dinner. Secretly, Lily puts sleeping powder in Nina's drink, making her late for a dance rehearsal the next morning. Both Lily and Nina were auditioning for the same part, and Nina learns that Lily got it because she herself wasn't there.
Mila Kunis was born in 1983 in the USSR. Her first popular film was Forgetting Sarah Marshall in 2008, and Black Swan is perhaps her best known film. Now living in America, Nunis started her acting career in 1994, when she was just eleven years old.
Vincent Cassel
Vincent Cassel takes on the part of Thomas Leroy, a worker at the ballet studio that both Nina and Lily perform at. A good friend of Nina, Lily comes along and he tells Nina that Lily outperforms her in many ways. Later, we see that he performs and act with Lily because Nina was not there (due to Lily drugging her) to do it. Although not for certain, Thomas seems to be in a little in love with Nina, and we see them kiss near the end of the movie.
Born in 1966, Vincent Cassel is a French actor. Currently residing in Brazil, he speaks French and English, reasoning how he became most acclaimed for the American Ocean's Twelve and Black Swan. Beginning to act in films in 1993, he is still at work in the profession.
Barbara Hershey
Barbara Hershey plays the role of the overprotective mother of Nina, as she warns her against many things regarding to ballet. Saying first that she should not be a ballerina, and second that she should avoid a dinner conference with the new dancer, Lily, she was pretty much correct. Overprotective, yes, but, in this scenario, it would have been better if Nina had just listened.
Barbara Hershey was born in 1948 and has been working in the acting profession for over 50 years. An American actress, some of her best-known jobs are A Killing in a Small Town and A World Apart. Born in Hollywood, she still resides there today at age 70.