Mahler was born July 7, 1860, in Kalischt (modern Kalištè), in what is now the Czech Republic. He studied at the Vienna Conservatory and in 1880 became assistant conductor at Bad Hall, Austria. He subsequently held posts as a conductor of opera in several central European cities. In 1897 he became artistic director of the Imperial Opera in Vienna. Through his efforts Vienna attained world prestige as an operatic center in the ensuing decade.
In 1907 Mahler went to New York City, where he conducted at the Metropolitan Opera from 1908 to 1910 and with the New York Philharmonic in 1910-11. He died in Vienna on May 18, 1911.

Of Mahler's symphonies, the unnumbered Das Lied von der Erde (Song of the Earth, 1908) and four of the nine numbered symphonies include solo voices with or without chorus. The song cycles Kindertotenlieder (Songs on the Deaths of Children, 1902) and Des Knaben Wunderhorn (The Boy's Magic Horn, 1888) exist in alternate versions with piano or orchestral accompaniment; Lieder eines fahrenden Gesellen (Songs of a Wayfarer, 1883) is orchestrally accompanied. Mahler also composed songs for voice and piano and left an unfinished tenth symphony.

Using the freedom that allowed Wagner and Bruckner to push almost to the limits of the traditional system of keys and chords, Mahler remained within that system, but he altered its basic premise so that most of his symphonies end in a key different from the initial key. As did Wagner and Bruckner, he employed vast orchestral resources; but his orchestration anticipated the 20th century in its emphasis on the color of individual instruments and small combinations of instruments, and its inclusion of unusual instruments such as the mandolin and harmonium. Likewise, he foreshadowed the 20th-century concern with counterpoint.