Gustav Mahler has been played over 30 times on NTS, first on 13 August 2017. Gustav Mahler's music has been featured on 30 episodes.

Gustav Mahler (7 July 1860 – 18 May 1911) was an Austro-Bohemian composer and conductor, regarded as a key figure bridging 19th-century Austro-German traditions and early 20th-century modernism. While his reputation as a conductor was well established during his lifetime, his compositions gained wider recognition only after periods of neglect, including bans on their performance in much of Europe during the Nazi era. After 1945, his works were rediscovered and have since become frequently performed and recorded.

Mahler was born in Bohemia, then part of the Austrian Empire, to Jewish parents of modest background. He showed musical talent early and graduated from the Vienna Conservatory in 1878. He held various conducting positions in European opera houses, eventually becoming director of the Vienna Court Opera in 1897. During his decade in Vienna, Mahler, who converted to Catholicism to secure the position, faced opposition from anti-Semitic elements in the press. Despite this, his innovative productions and high standards established his reputation as a leading opera conductor, especially noted for interpretations of Wagner, Mozart, and Tchaikovsky. Later in life, he briefly directed the Metropolitan Opera and the New York Philharmonic.

Mahler's compositional output is relatively small, as he composed mainly while working full-time as a conductor. Apart from early works, such as a movement from a piano quartet composed during his studies, his major works typically require large orchestras, symphonic choirs, and operatic soloists. His music was often controversial at first, with some works, including his Second Symphony and the successful premiere of his Eighth Symphony in 1910, receiving earlier acclaim. Composers associated with the Second Viennese School, such as Arnold Schoenberg, Alban Berg, and Anton Webern, were influenced by Mahler, as were later figures including Dmitri Shostakovich and Benjamin Britten. The International Gustav Mahler Society was founded in 1955 to celebrate his life and work.