Barr was born to a French mother and an American father working in the US Armed Forces. He is fluent in both French and English. Barr was born in West Germany where his father was stationed, and lived an itinerant childhood. His family moved to France in 1968, then to California in 1974. Barr's parents wished for him to join the armed forces, but he was unwilling to follow in his father's footsteps. He studied philosophy at the University of California, Los Angeles, the Paris Conservatoire and the Sorbonne. He moved to London to pursue an education in drama at the Guildhall School of Music and Drama. Barr began working in theatre in France in 1986. After finding work in television, and film,, he was cast in the tremendously successful The Big Blue. Luc Besson cast him in the role of French diver Jacques Mayol, alongside Rosanna Arquette and Jean Reno. The Big Blue was the most financially successful film in France in the 1980s. In 1991, Barr starred in Danish director Lars von Trier's Europa, marking the beginning of a long friendship as well as a significant professional relationship. He went on to appear in von Trier's Breaking the Waves, Dancer in the Dark, Dogville, Manderlay, The Boss of It All and Nymphmaniac. In 2005 he starred in the French film Crustacés et Coquillages. In 1999 he starred in the French cinéma du corps/cinema of the bodydrama film, Don't Let Me Die on a Sunday, directed by Didier Le Pêcheur. Barr's collaboration with von Trier put him on track to start directing his own work. He debuted in 1999 as a director, screenwriter and producer with the intimate love storyLovers. The film became the first part of a trilogy; the films that followed were the drama Too Much Flesh and the comedy Being Light, which he co-directed with Pascal Arnold. Barr and Pascal also directed the 2006 film Chacun sa nuit, where they first discovered Lizzie Brocher, Arthur Dupont and Karl E. Landler. This was followed by another collaboration in 2012, Sexual Chronicles of a French Family. In 1997 Barr appeared in The Scarlet Tunic, produced by Zigi Kamasa. He appeared as Hugo in The Red Siren in 2002 and played divorce lawyer Maître Bertram in the 2003 Merchant Ivory film le Divorce. He appeared as the titular character in the video for Blur's 1996 single, "Charmless Man". In 2010 he starred in Kim Nguyen's film City of Shadows . Barr played author Jack Kerouac in the 2013 film adaptation of the Beat Generationautobiographical novelBig Sur.
