French composer. Born into near poverty, he showed an early gift for the piano. He entered the Paris Conservatoire in 1873, and soon thereafter he was employed as pianist by Nadezhda von Meck, Pyotr Tchaikovsky's patroness. Influenced by the Symbolist poets and Impressionist painters, he was early inclined toward a compositional style of great originality, shunning the strictures of traditional counterpoint and harmony to achieve new effects of great subtlety.

After traveling in Europe and Russia, Debussy settled down in Paris in 1887 and devoted himself to composing for the rest of his life. In his music he developed a new fluidity of form and explored unusual harmonic relationships and dissonances. By making use of the whole-tone scale, instead of the traditional scale of Western music, he achieved new nuances of mood and expression, as in his famous tone poem Prélude à l'après-midi d'un faune (Prelude to the Afternoon of a Faun, 1894). Inspired by a pastoral poem of Mallarmé, it is one of Debussy's most sensuous and evocative orchestral works, lending itself perfectly to ballet. Other outstanding orchestral pieces are his Nocturnes (1899) and La Mer (The Sea, 1905). His piano works exploit to the utmost the subtle coloristic possibilities of the instrument. Among them are Suite bergamasque (pub. 1905), containing the popular Clair de lune; Estampes (1903); The Children's Corner (1908); 24 preludes, including La Cathédrale engloutie (1910); and 12 études. He also wrote many exquisite songs and an opera, Pelléas et Mélisande (1892–1902), based on the drama by Maeterlinck.

The important piano music begins with works which, Verlaine fashion, look back at rococo decorousness with a modern cynicism and puzzlement (Suite bergamasque, 1890; Pour le piano, 1901). But then, as in the orchestral pieces, Debussy began to associate his music with visual impressions of the East, Spain, landscapes etc, in a sequence of sets of short pieces. His last volume of Etudes (1915) interprets similar varieties of style and texture purely as pianistic exercises and includes pieces that develop irregular form to an extreme as well as others influenced by the young Stravinsky (a presence too in the suite En blanc et noir for two pianos, 1915). The rarefaction of these works is a feature of the last set of songs, the Trois poèmes de Mallarmé (1913), and of the Sonata for flute, viola and harp (1915), though the sonata and its companions also recapture the inquisitive Verlainian classicism The planned set of six sonatas was cut short by the composer's death from rectal cancer.