Toscanini studied at the conservatories of Parma and Milan, intending to become a cellist. At the age of 19, when playing at the opera house at Rio de Janeiro, he was called upon to fill in for the conductor and performed Giuseppe Verdi's Aida from memory. He came into prominence as a conductor in Italy and elsewhere and was appointed musical director of La Scala, Milan, in 1898, and of the Metropolitan Opera, New York City, in 1908. He conducted the New York Philharmonic-Symphony Orchestra from 1928 to 1936 and appeared with orchestras all over the world, except those of Italy and Germany during the Fascist regimes. From 1937 to 1954 he directed the NBC Symphony, an orchestra sponsored by the U.S. radio network.

Toscanini became principally known for his readings of the operas of Verdi and the symphonies of Beethoven, and he gave remarkable performances of the music of Wagner. His interpretations were notable for detail of phrasing, dynamic intensity, and an essentially classical conception of form. His phenomenal memory stood him in good stead when, suffering from poor eyesight, he was obliged always to conduct from memory. He commanded from the artists who worked under him a devotion that often made them reach something like his own fervour.