Bonnaire was born in the town of Gannat, Allier, in the Auvergne region. She was born into a working-class family, the seventh of eleven children. Her acting career began at the age of 16 in 1983, when she starred in the Maurice Pialat film À NOS amours. She played a girl from Paris beginning her sexual awakening. In 1984, she was awarded the César Award for Most Promising Actress.
Her international breakthrough came in 1985 when she played the main character in Sans toit ni loi (Vagabond), directed by Agnès Varda, for which she won her second César Award. She portrays a vagrant who fails both physically and morally. The film premiered at the 42nd Venice International Film Festival where it won the Golden Lion prize. The jury deemed Bonnaire's performance as amongst the best of the year, but decided against awarding the Volpi Cup for Best Actress prize because both of the actresses they judged to have given the best performances were in films that won major awards.
Bonnaire worked again with Pialat on the film Sous le soleil de Satan (Under the Sun of Satan) which won the Palme d'Or at the 1987 Cannes Film Festival. The film Monsieur Hire directed by Patrice Leconte followed in 1989, along with further work with Directors Jacques Doillon and Claude Sautet.
Bonnaire has a daughter, Jeanne, from a relationship with actor william Hurt, whom she met in 1991 during filming of the Albert Camus novel La Peste (The Plague). They acted together in Secrets Shared with a Stranger (1994). Since March 2003 she has been married to actor and Screenwriter Guillaume Laurant, with whom she has had a second daughter, Adèle.
In 1995, she starred as an apparently simple maid in Claude Chabrol's widely acclaimed thriller La Cérémonie. The film and its stars won awards internationally, including for Best Actress at the 52nd Venice Film Festival for both Bonnaire and co-star Isabelle Huppert.
In 2004, she starred in another Patrice Leconte's film: Intimate Strangers, which was an arthouse box office hit in the United States.
In 2017, Sandrine Bonnaire starred in Prendre le large a Gaël Morel's social film about reverse immigration. At the 8th Magritte Awards, she received an Honorary Magritte Award from the Académie André Delvaux.
