Gaspard Ulliel

Ulliel was born in the Paris suburb of Neuilly-sur-Seine to Christine, a stylist and runway show producer, and Serge Ulliel, a fashion designer. Ulliel was an only child. His great-grandfather, Raoul Ulliel (1889–1943), was a bronzesmith who distinguished himself in combat during World War I. His paternal grandmother was of Italian and Spanish descent.

He had a scar on his left cheek as a result of a doberman attacking him with its claws when he attempted to ride the dog like a horse at the age of six. He once quipped that the scar increased his emotional acting abilities because it looked like a dimple. His obituary in the French newspaper Libération described him as having the "most famous scar in French cinema".

Ulliel attended the bilingual school École Jeannine Manuel in Paris where he learned English.

Ulliel wanted to be a jazz musician and even tried playing the saxophone for a couple of years, but he quit because he thought he wasn't talented. He also learned how to play the piano. He was also interested in architecture and photography.

He dreamed of becoming a film director and attended the University of Saint-Denis in Paris, where he studied cinema for two years until he quit to focus on his acting career.