Born in Paris to a Polish-Jewish family who moved to Krakow in 1937. Polanski's father, Ryszard Liebling (who changed his name to Polanski at the request of his fiancée and later second wife, Wanda Zajączkowska, after World War II), was a painter. His mother, Bula (Bella), was born in Russia. Polanski's parents were agnostic, his father Jewish and his mother Catholic.
During the war he was imprisoned in the Krakow ghetto, and later went into hiding under the name Roman Wilk. In 1954 he enrolled in directing studies in Lodz, from which he graduated without a diploma. In 1959 he married the actress Barbara Kwiatkowska, but the marriage broke up after three years. He collaborated with Andrzej Wajda, a famous Polish director, starring in his films (The Generation (1954), The Innocents, Revenge).
Later, he went to Paris, and immediately after returning to Poland in 1961, he made Knife in the Water, which was nominated for an Oscar, which opened the door for Polanski's international directing career. He went back to France to work with Catherine Deneuve on Repulsion, at the same time directing Cul-de-Sac, which was a great success in Britain. On 20 January 1968, he married Sharon Tate and left for Hollywood the same year. There he became famous for such films as Rosemary's Baby (1968, two Oscar nominations, one win), Chinatown (1974, eleven Oscar nominations, one win) with Jack Nicholson, Tess (1979, six Oscar nominations, three wins), thanks to the films.
On 9 August 1969, Polanski's eight-months-pregnant wife, Sharon Tate, was brutally murdered.
In 1978, Polanski was accused of raping thirteen-year-old Samantha Geimer with drugs and alcohol. He confessed to having sex with a minor at the prosecution. The court gave Polanski 90 days to complete the project, but the director fled to Paris, where he still lives, before the ruling was announced. In his autobiography, Roman by Polanski accuses Samantha's mother of setting up her daughter and blackmailing her for money.
In 2008, when the prosecutor's office reopened the case of Samantha Geimer and Roman Polanski, the girl filed a motion with the court asking the court not to pursue the case in order to spare her and her family from any unpleasantness, but the motion was not granted. In a recent documentary on Polanski, Roman Polanski: Wanted and Desired, further evidence was uncovered that the 1978 trial against Polanski was conducted in bad faith, with the appointed judge, Laurence J. Rittenband (d. 1993), wanting to convict the director in order to boost his popularity. Geimer admitted that he had agreed to make love, and a few years earlier said that he forgave Polanski and wished he could return to the USA.
On 30 August 1989, Geimer married the French actress, model and singer Emmanuelle Seigner, with whom he had two children, a daughter, Morgan, and a son, Elvio.
After the film was released, Geimer received the Palme d'Or at the Cannes Film Festival for Best Picture. In 2003, he received an Oscar for The Pianist, which he did not accept due to a pending charge of rape against Samantha Geimer.