Born in Paris, Bruneau studied the cello as a youth at the Paris Conservatory and played in the Pasdeloup orchestra. He soon began to compose, writing a cantata, Geneviève de Paris, while still a young man. In 1884, his Ouverture heroique was performed, followed by the choral symphonies Léda (1884) and La Belle au bois dormant (1886). In 1887, he produced his first opera, Kérim.
The following year, Bruneau met Émile Zola, launching a collaboration between the two men that would last for two decades. Bruneau's 1891 opera Le Rêve was based on the Zola story of the same name, and in the coming years Zola would provide the subject matter for many of Bruneau's works, including L'attaque du moulin (1893). Zola himself wrote the libretti for the operas Messidor (1897) and L'Ouragan (1901). Other works influenced by Zola include L'Enfant roi (1905), Naïs Micoulin (1907), Les Quatres journées (1916), and Lazare (produced posthumously in 1954). Other operatic works by Bruneau contained themes by Hans Christian Andersen (Le Jardin du Paris in 1923) and Victor Hugo (Angelo, tyran de Padoue in 1928). Bruneau's orchestral works show the influence of Wagner. His other works include his Requiem (1888) and two collections of songs, Lieds de France and Chansons à danser.