She was born Sylvette Herry in Paris. Her stage name, Miou-Miou (a reference to the sound of a cat), was given to her by Coluche. She was raised in Paris by her mother, a greengrocer. After studying acting she worked in improvisational theater with Coluche and Patrick Dewaere, joining with them to help found the new comedy theatre Café de la Gare. She made her film debut in La vie sentimentale de Georges Le Tueur and La Cavale (both 1971).
She showed a mixture of innocence and strength in her roles. In 1973 she appeared in three films, Elle court, elle court la banlieue, Les granges brulées and Les aventures de Rabbi Jacob. Her big break came with Blier's Les Valseuses (Going Places), released in 1974. After her role in Les valseuses, she began getting leading roles in comedy and drama. Through the 1970s, she had roles in such films as F comme Fairbanks (1976), Alain Tanner's Jonah Who Will Be 25 in the Year 2000 (1976), Losey's Roads to the South (1978) and La dérobade (Memoirs of a French Whore, 1979) directed by Daniel Duval, in which she portrayed a young prostitute. She received a César Award for that role. Many of these 1970s films were seen in North America in art-house venues. In 1976 she appeared in one of the last spaghetti westerns, Damiano Damiani's A Genius, Two Friends, and an Idiot.
Miou-Miou does not consider herself a "star". She was quoted as saying in 1989, "I turned down dinner with Mickey Rourke. Because he's a star. To me, a star is inaccessible, mysterious, an impossible dream – and should stay that way. Adjani's a star. Deneuve's a star. Not me".
The 1990s saw her in Louis Malle's May Fools (1990), Deray's thriller Netchaïev is back, the comedy Un indien dans la ville (1994), and The Eighth Day (1996) and Dry Cleaning in 1997. She appeared opposite Gérard Depardieu in a new production of Émile Zola's Germinal (1993). By now in her fifties, her film roles have abated, as she also began to appear in theatre. 2001 saw her in Agathe et le grand magasin and in 2004 she appeared in L'après-midi de monsieur Andesmas, among other films.
By 2006, she had 70 films to her credit. Through the 1980s she was in such films as La gueule du loup (1981), Guy de Maupassant (1982), Kurys' Entre nous (1983) with Isabelle Huppert, Blanche et Marie (1984), Evening Dress (1986), and Deville's La lectrice (The Reader, 1988). She played opposite Lee Marvin (in one of his last roles) in Boisset’s Dog Day in 1984.
