Nézet-Séguin was born in Montreal on March 6, 1975. He began studying piano at age five and decided on a career as a conductor at age ten after attending a performance by the Orchestre Symphonique de Montréal under Charles Dutoit. He studied piano, chamber music, conducting, and composition at the Conservatoire de Musique du Québec, and he studied choral conducting at Westminster Choir College. When he was 14, he began leading rehearsals of the Chœur polyphonique de Montréal at the Montréal Cathedral; he became the group's conductor in 1994, at age 19. That same year, Nézet-Séguin, who had a lifelong admiration for the work of Carlo Maria Giulini, was invited to follow the famed conductor for a year, observing rehearsals and concerts and working extensively with Giulini during his final year of public performances. In 1995, Nézet-Séguin founded Le Chapelle de Montréal, a vocal and instrumental group that began with a focus on the Baroque. He continued performing with this group until 2002.
From 1998 until 2002, Nézet-Séguin was the chorus master and assistant conductor of L'Opéra de Montréal. In 2000, he was named the artistic director and principal conductor of Orchestre Métropolitain du Montréal. From 2008 until 2018, he served as conductor of the Rotterdam Philharmonic Orchestra, succeeding Valery Gergiev. From 2008 until 2014, he was the principal guest conductor of the London Philharmonic Orchestra. In 2012, Nézet-Séguin succeeded Dutoit as the music director of the Philadelphia Orchestra. In 2018, he was named the music director of the Metropolitan Opera, following annual appearances leading the company. He also took on the title of Honorary Conductor with the Rotterdam Philharmonic in 2018. The following year, after extending his contract several times, the Orchestre Métropolitain du Montréal awarded Nézet-Séguin a lifetime contract.
Nézet-Séguin records mainly for Deutsche Grammophon, but he has also recorded for several other labels. In addition, he is active as a pianist and is featured on a number of discs as a soloist or accompanist. In 2019, he released several albums, including Verdi, with the Orchestre Métropolitain du Montréal and soloist Ildar Abdrazakov. An unusually active 2021 saw eight releases, including his first-ever solo piano album, Introspection, and a Grammy Award-winning recording of Florence Price's first and third symphonies with the Philadelphia Orchestra. That year, he was the subject of Patrick Delisle-Crevier's book about his life and career, Raconte-moi Yannick Nézet-Séguin. The following year, he led the Chamber Orchestra of Europe in a cycle of Beethoven's symphonies, and he backed Lisa Batiashvili on her album Secret Love Letters, once again with the Philadelphia Orchestra. ~ Stephen Eddins & Keith Finke, Rovi