Gayet made her acting debut in a 1992 episode of the French TV series Premiers baisers, and had her first film role as an extra in Three Colors: Blue (1993), but her first role of public note was in the 1996 comedy Delphine 1, Yvan 0 by Dominique Farrugia.
In 2003, Gayet married author and Screenwriter Santiago Amigorena, but they divorced in 2006. The couple have two children. She then had a controversial relationship with Alexis Mercier, a French singer known as Aldène.
In 2007, she founded her own production company, Rouge International, with Nadia Turincev and produced films such as Fix me by Palestinian Raed Andoni and Bonsai by Cristian Jimenez of Chile.
On 27 March 2014, French court ordered Closer magazine to pay Actress Julie Gayet €15,000 ($20,700) for publishing photos that revealed an affair between her and President Hollande. In November 2014, she was photographed with Hollande at the Élysée Palace gardens; it was revealed that her affair with Hollande was ongoing and that she was spending at least four nights a week with him there.
