Breillat was born in Bressuire, Deux-Sèvres, but grew up in Niort. She decided to become a writer and director at the age of twelve after watching Ingmar Bergman's Gycklarnas afton, believing she had found her "fictional body" in Harriet Andersson's character, Anna.
She started her career after studying acting at Yves Furet's "Studio d'Entraînement de l'Acteur" in Paris together with her sister, actress Marie-Hélène Breillat (born 2 June 1947) in 1967. At the age of 17, she had her novel published, l'Homme facile (Easy Man). The French government banned it for readers under 18 years old. A film based on the novel was made shortly after the publication of the book, but the producer went bankrupt and the distributor Artedis blocked any commercial release of the film for twenty years although it had been given an R rating.
Breillat is known for films focusing on sexuality, intimacy, gender conflict, and sibling rivalry. Breillat has been the subject of controversy for her explicit depictions of sexuality and violence. She cast the pornstar Rocco Siffredi in her films Romance (Romance X, 1999) and Anatomie de l’enfer (Anatomy of Hell, 2004). Her novels have been best-sellers.
Her work has been associated with the cinéma du corps/cinema of the body genre. In an interview with Senses of Cinema, she described David Cronenberg as another filmmaker she considers to have a similar approach to sexuality in film.
Though Breillat spends most of her time behind the camera, she has acted in a handful of movies. She made her film debut in Bernardo Bertolucci's Last Tango in Paris (1972) as Mouchette, a dressmaker, alongside her sister Marie-Hélène Breillat.
In 2004, Breillat suffered a cerebral hemorrhage, causing a stroke that paralyzed her left side. After five months of hospitalization and a slow rehabilitation, she gradually returned to work, producing Une vieille maîtresse (The Last Mistress) in 2007. This film was one of three French films officially selected for the Cannes Film Festival of that year.
In 2007, Breillat met notorious conman Christophe Rocancourt, and offered him a leading role in a movie that she was planning to make, based on her own novel Bad Love, and starring Naomi Campbell. Soon after, she gave him €25,000 to write a screenplay titled La vie amoureuse de Christophe Rocancourt (The Love Life of Christophe Rocancourt), and over the next year and a half, would give him loans totalling an additional €678,000. In 2009, a book written by Breillat was published, in which she alleged that Rocancourt had taken advantage of her diminished mental capacity, as she was still recovering from her stroke. The book is titled Abus de faiblesse, a French legal term usually translated as "abuse of weakness". In 2012, Rocancourt was convicted of abus de faiblesse for taking Breillat's money, and sentenced to prison.
In September 2010, Breillat's second fairy-tale based film, La belle endormie (Sleeping Beauty), opened in the Orizzonti sidebar in the 67th Venice Film Festival.
As of 2011, although Breillat had moved on to other projects, she still hoped to film Bad Love, but had not yet been able to find financing to do so. However somewhat ironically, a film adaptation of her book Abus de faiblesse, directed by Breillat and starring Isabelle Huppert, began production in 2012, and was screened at the 2013 Toronto International Film Festival.
It has been noted that "Breillat remains committed to the long take, particularly during scenes of sexual negotiation, a technique that showcases her performers' virtuosity as well as emphasizes the political and philosophical elements of sex. In both Fat Girl and Romance, for example, key sex scenes possess shots lasting over seven minutes."Les Vêtements de mer