Marion Cotillard was born in Paris and grew up around Orléans, Loiret in an artistically-inclined, "bustling, creative household". Her father, Jean-Claude Cotillard, is an actor, teacher, former mime, and 2006 Molière Award-winning director of Breton descent Her mother, Niseema Theillaud, is also an actress and drama teacher. Marion began acting during her childhood, appearing on stage in one of her father's plays.

After a few roles on television, her career as a film actress began in the mid-1990s with small but noticeable roles in such films as Pierre Grimblat's Lisa alongside the iconic Jeanne Moreau, Swiss novel-adaptation drama War In The Highlands, Coline Serreau's comedy La Belle Verte, or Alexandre Aja's anticipation fantasy Furia among other participations in established directors' productions. She rose to prominence in the late 1990s when she was cast in the Luc Besson production Taxi (1998) as Lili Bertineau, a minor role that she reprised in two sequels. She then earned very good reviews and the attention of cinephiles via her portrayal of twins who exchange their lives after one of them dies in Les Jolies Choses/Pretty Things adapted from the work of subversive feminist novelist Virginie Despentes in which she sang live on stage a couple of songs she had co-written.

In 2003, she had a small role in Tim Burton's film, Big Fish, which introduced her to English-speaking audiences. She also played Sophie Kowalski in Yann Samuell's Jeux d'enfants (English title: Love Me If You Dare), in which she played a complex yet appealing modern romantic lead. She appeared in two critically successful films in 2004: A Very Long Engagement, where Cotillard further demonstrated the range of her abilities by playing the murderous Tina Lombardi (garnering the César Award for Best Actress in a Supporting Role), and the drama mystery Innocence.

2005 saw Abel Ferrara offering her a small role alongside Forest Whitaker(who would present her the Oscar two years later) in his religious movie Mary while she also played in Burnt Out, Fabienne Godet's study of social oppression and stresses of corporate culture. In 2006, she appeared in Ridley Scott's A Good Year, Belgian comedy Dikkenek and learnt to play the cello for her role as a musician in the satirical coming of age movie You and Me.

She was chosen by director Olivier Dahan to portray the iconic French singer Édith Piaf in the biopic La Môme (English title: La Vie En Rose) before he had even met her, saying that in the eyes of Édith Piaf he noticed a similarity with Marion's own.

On February 10, 2008, Cotillard became the first French actress to be awarded the BAFTA Award for Best Actress in a Leading Role since the BAFTAs in 1969 combined the Best British and Best Foreign actress award into one Best Actress category. She is also the first actress to be nominated for an Academy Award for a French language performance since Catherine Deneuvefor Indochine in 1992. She is the first actress to win a Golden Globe for a foreign language performance since 1972, when Liv Ullmann won for The Emigrants. She is also the very first person to win a (Comedy or Musical) Golden Globe for a foreign language performance. As La Vie En Rose was also a Czech production, Marion Cotillard was nominated for the Czech Lion for "Best Actress in a Leading Role" on February 21.

On February 22, 2008 she was awarded the César Award for Best Actress, and two days later she received the Academy Award for Best Actress. After Simone Signoret in 1959, Marion Cotillard is the second French cinema actress to win an Academy Award for Best Actress, though French expatriate Claudette Colbert was given an Oscar in 1934. She is the first Best Actress winner in a non-English language performance since Sophia Loren's win in 1961. She is also the first and so far only winner of an Academy Award for a performance in the French language.

Cotillard is currently in a relationship with French actor/director Guillaume Canet They co-starred in the 2003 French film Love Me If You Dare. The couple's relationship is widely reported in the French press, and they have been dubbed the French version of "Brangelina." Despite this, many reports say the couple prefers to live a simple lifestyle, and they are often spotting in cafes and shopping together in Paris.