Haïm was born in Paris on May 11, 1962. In her deep ancestry was a family of Breton organ makers, and her stepfather passed time as friends with both András Schiff and Zoltán Kocsis. Haïm was inspired to take up the piano, and she and her siblings performed chamber music at these high-level gatherings. She soon decided on a musical career. Haïm attended the Conservatoire de Paris (the CNSMDP) for 13 years, starting on piano but switching to harpsichord in her mid-twenties because she wanted to participate in a performance of Bach's St. Matthew Passion and couldn't think of another way to become involved. Among her teachers at the Paris Conservatoire were Kenneth Gilbert and Christophe Rousset (with whom she appeared as harpsichordist on a 1996 recording of Handel's Riccardo Primo), and she was soon pulling down top prizes. Her harpsichord skills were spotted by conductor William Christie, and for a decade, Haïm performed with his ensemble, Les Arts Florissants. Working with Christie, she absorbed the principles of conducting. She also performed Baroque and Classical repertory with big-name conductors such as Simon Rattle, who would later encourage her in her own conducting efforts. She was also a noted accompanist who worked with Cecilia Bartoli, among others.
Haïm's conducting debut was as unplanned as her turn toward the harpsichord; a group of instrumentalist friends wanted to practice working with singers, and Haïm agreed to helm an impromptu ensemble. She began to find opportunities as a Baroque opera conductor, and in 2000, she formed an ensemble of her own, Le Concert d'Astrée. That put Haïm and her enthusiasm squarely in the spotlight ("like a ballerina on speed" was the Independent's description of Haïm in rehearsal), and engagements and support began to flow her way. Quite early on, Haïm made her recording debut with Le Concert d'Astrée, in a 2002 recording of Handel's Arcadian Duets on the Erato/Virgin label, featuring a high-powered group of singers, including Natalie Dessay. That year, Haïm conducted Monteverdi's Orfeo at the Barbican in London in a series of six sold-out performances featuring star tenor Ian Bostridge. She made numerous guest-conducting appearances but has mostly declined chances to move into mainstream repertory. Haïm conducted Orfeo in 20 performances across France in the 2005-2006 season. She was the first woman conductor at the Lyric Opera of Chicago, leading Handel's Giulio Cesare in 2007. As her reputation grew, many groups invited her to guest conduct concerts and recordings, as Concerto Köln did in 2010 for the album Caldara in Vienna. Haïm continues to conduct Le Concert d'Astrée and maintains a busy schedule of guest appearances, including some with full symphony orchestras. By 2022, Haïm had appeared on more than 85 albums, including that year's Une nouvelle fête Baroque! ~ James Manheim, Rovi