Debussy was born in Paris in 1862, and received his formal musical education at the Paris Conservatoire, where he was trained in traditional Romantic techniques and sonorities. A facile and talented composer, he was early on enough of a traditionalist to win First Prize at the 1884 Prix de Rome competition - the same contest that Debussy's brilliant contemporary, Ravel, would enter several times but never win, in part due to Ravel's revolutionary sense of harmony and rhythm. Soon after this triumph, however, Debussy started to reject many of the precepts of his training, including the importance of the Germanic musical tradition, of which Wagner was the most oft-cited example.

As Debussy set off to write his own style of music, he found himself in the heady cultural hotbed of late-19th century Parisian society, a climate enriched by Russian music, non-western idioms demonstrated at the Paris Exposition of 1889, and Symbolist poetry, as well as a revolution in visual arts. Paris was a remarkable melting pot of cultural diversity and artistic influence, and the young Debussy began to make these influences heard in his music, which placed an emphasis on aural images, clusters and metaphors rather than on traditional musical devices. His early, pre-Impressionist compositions for piano are remarkable in their craft, especially the Suite bergamasque (1893). The same year, he premiered the seminal Quartet in G minor for Strings, and people started to scratch their heads in confusion, so novel was Debussy's sound. Critics complained that Debussy was a self-indulgent non-conformist. The next year brought the brilliant Prélude à l'après-midi d'un faune (Prelude to the Afternoon of a Faun), Debussy's first orchestral work and a masterpiece of novel ensemble texture and harmonic innovation. The work was inspired by a Stephane Mallermé poem of the same name, and the music roughly evokes each scene in the poem.

Later works exhibited a more fully-developed "Impressionistic" style - notably Estampes, Images, and La Mer. Another seminal work was Debussy's one opera, Pelléas et Mélisande (1902), wherein he used musical imagery and dramatic devices that flew in the face of Wagner's dominant style. Later pieces ushered in such radical tonal juxtapositions that Debussy is often cited as the father of atonality - which at that time was new and unchartered territory.