Alexandre Desplat was born in Paris in 1961. At the age of 6, he started taking piano lessons and continued with flute and trumped lessons at 8 and 10, respectively. At the same time, he wrote his first compositions and later continued his studies at the Conservatoire de Paris.

Desplat wrote his first film score for Robert Guédiguian's comedy »Ki lo sa« in 1981. Since then, Alexandre Desplat scored more than 160 movies. He received 8 Academy Award and 8 Golden Globe nominations and was awarded with an Oscar, Golden Globe and 2 Grammys.

In his early days, Desplat collaborated with such renowned European film directors like Jacques Audiard, Marleen Gorris and Patrice Leconte. With his preference for lyrical, elegant orchestrations and precise dramatization, Desplat soon received international attention.

Im 2003, Alexandre Desplat composed the music to Peter Webber's historical drama The Girl with a Pearl Earring starring Scarlett Johansson and Colin Firth. The sensual film score was nominated for the Golden Globe, the British Academy Film Award and the European Film Price. It marked his international break through as a film composer and made him known in Hollywood. 

One year later, he was again praised by critics for his music to Jonathan Glazer's drama Birth with Nicole Kidman, cementing his position in the A-liga of Hollywood composers. 

Since then, Desplat has become indispensable for such leading directors like Roman Polanski, Stephen Frears, Wes Anderson, Ang Lee, David Fincher, Tom Hooper, Terrence Malick, Ben Affleck, Kathryn Bigelow and George Clooney.

For his music to Jacques Audiard's drama The Beat that my Heart skipped, Desplat received the Silver Bear at the Berlin Film Festival 2005 as well as the César in 2006. He subsequently received two Golden Globe nominations in 2006 and 2007 for his scores to the political drama Syriana (2005) and the romantic drama The painted Veil with Naomi Watts, the latter finally earning him the Golden Globe. In 2007, Desplat also received an Oscar nomination as well as the European Film Price award for his music to Stephen Frears' Elizabeth II. biography The Queen.

He was subsequently nominated for an Academy Award for the scores to David Fischer's screen adaptation of The Curious Case of Benjamin Button (2008) and Wes Anderson's animated film Fantastic Mr. Fox (2009). In 2010, Desplat scored Harry Potter and the Deathly Hallows -1 &2, Roman Polanki's The Ghost Writer, Chris Weitz's Twilight – The New Moon and Tom Hooper's The Kings Speech, earning him his fourth Oscar nomination within five years. In 2012, he composed the music for  Ben Affleck's Argo, which received the Academy Award for the best movie of the year and the fifth Oscar and Golden Globe nomination for Desplat. In 2013, he was again nominated for an Oscar for Steven Frear's Philomena. One year after, Desplat composed the soundtrack for Godzilla and received two Oscar nominations: for Morten Tyldum’s The Imitation Game and Wes Anderson’s The Grand Budapest Hotel. His music for The Grand Budapest Hotel was finally awarded with the Oscar.

Alexandre Desplat can also be seen as an actor in Josiane Balasko's comedy (1991) alongside Daniel Auteuil and with Matt Damon in George Clooney's Monuments Man (2014). 

Desplat also writes music for the Comédie Francaise as well as Ballet and is a  jury member of the Festival de Cannes as well as jury president of the Venice Film Festival.