Mia Farrow
Mia Farrow was a twenty-three-year-old actress known primarily for her role in the television series Peyton Place at the time that Polanski cast her as Rosemary. She was also by 1968 a tabloid regular given her illustrious family (daughter of director John Farrow and actress Maureen O'Sullivan) and publicized marriage to Frank Sinatra. For her role as Rosemary Woodhouse, Mia Farrow won the Golden Globe Award for "Most Promising Female Newcomer."
John Cassevetes
At the time of Rosemary's Baby's production, John Cassevetes was an established actor and director who had already made the films Shadows (1959), Too Late Blues (1961), and A Child is Waiting (1963). A known improvisor, he apparently quarreled with Polanski often on set.
Ruth Gordon
Ruth Gordon was an established stage actress and Hollywood player who had already been nominated for an Academy Award at the time of Rosemary's Baby's production. For her role as Minnie Castevet she won an Academy Award for Best Supporting Actress. The character of Minnie Castevet was meant to embody many of the star-making qualities (wit, warmth, quickness) that had originally made Ruth Gordon a Broadway contender.
Sidney Blackmer
Sidney Blackmer was a veteran actor with extensive ties to early twentieth-century American theater, having performed on Broadway as early as 1917. He won the Tony Award for Best Actor in 1950 for Come Back, Little Sheba. Rosemary's Baby was the penultimate film credit on a career spanning over six decades.
