Schoenberg's approach, both in terms of harmony and development, is among the major landmarks of 20th-century musical thought; at least three generations of composers in the European and American traditions have consciously extended his thinking or, in some cases, passionately reacted against it. During the rise of the Nazi Party in Austria, his music was labeled as degenerate art.
Schoenberg was widely known early in his career for his success in simultaneously extending the traditionally opposed German Romantic styles of Brahms and Wagner. Later, his name would come to personify pioneering innovations in atonality (although Schoenberg himself detested the term "atonality" as inaccurate in describing his intentions) that would become the most polemical feature of 20th-century art music. In the 1920s, Schoenberg developed the twelve-tone technique, a widely influential compositional method of manipulating an ordered series of all twelve notes in the chromatic scale. He also coined the term developing variation, and was the first modern composer to embrace ways of developing motifs without resorting to the dominance of a centralized melodic idea.
Schoenberg was also a painter, an important music theorist, and an influential teacher of composition; his students included Alban Berg, Anton Webern, Hanns Eisler, Egon Wellesz, and later John Cage, Lou Harrison, Earl Kim, Leon Kirchner, and other prominent musicians. Many of Schoenberg's practices, including the formalization of compositional method, and his habit of openly inviting audiences to think analytically, are echoed in avant-garde musical thought throughout the 20th century. His often polemical views of music history and aesthetics were crucial to many significant 20th-century musicologists and critics, including Theodor W. Adorno, Charles Rosen and Carl Dahlhaus, as well as the pianists Artur Schnabel, Rudolf Serkin, Eduard Steuermann and Glenn Gould.
Schoenberg's archival legacy is collected at the Arnold Schönberg Center in Vienna.