Wiazemsky spent her early years abroad following her father's postings around the world, before returning to Paris in 1962. She graduated from the high school Ecole Sainte Marie de Passy in Paris.
During the 1966 filming of Au Hasard Balthazar, Director Robert Bresson proposed to her several times, though she refused. In 1967, she married Jean-Luc Godard, and subsequently starred in several of his films; the marriage officially ended in divorce in 1979, though the couple had already separated as early as 1970.
Wiazemsky subsequently developed a relationship with Godard, and married him one year later, in 1967. She starred in several of his films, including La Chinoise (1967), Week End (1967), and One Plus One (1968).
In addition to acting, Wiazemsky has written several novels, including Canines (1993), Une Poignée de Gens (1998), and Aux Quatre Coins du Monde (2001). Hymnes à l’Amour was filmed in 2003 as Toutes ces belles promesses (All the Fine Promises), directed by Jean-Paul Civeyrac and starring Valérie Crunchant and Bulle Ogier. Her novel Jeune Fille (2007) was based on her experience of starring in Au Hasard Balthazar. Her novel Hymnes à l’Amour (1996), which was made into a film called All the fine promises directed by Jean-Paul Civeyrac.
Wiazemsky died of breast cancer on 5 October 2017, aged 70.