During the early 1930s, Leibowitz studied composition and orchestration with Maurice Ravel in Paris, where he was introduced to Arnold Schoenberg's twelve-note technique by the German pianist and composer Erich Itor Kahn. He subsequently studied with Schoenberg's pupil Anton Webern. Many of the works of the Second Viennese School were first heard in France at the International Festival of Chamber Music established by Leibowitz in Paris in 1947. Leibowitz was highly influential in establishing the reputation of the School, both through teaching in Paris after WWII and through his book Schoenberg et son école, published in 1947 and translated by Dika Newlin as Schoenberg and his School (US and UK editions 1949). The book was among the earliest theoretical treatises on Schoenberg's 12-tone method of composition, wherein Leibowitz (and Humphrey Searle) were among the first theorists to coin the term "serialism". Leibowitz's advocacy of the Schoenberg school was taken further by two of his pupils, Pierre Boulez and Jacques-Louis Monod, each taking different paths in promoting the music of Schoenberg, Webern and the development of serialism. His American students included the composers Will Ogdon and Janet Maguire, the conductor David Montgomery, and the avant-garde film director-animator John Whitney.
As a conductor, Leibowitz, who studied in Paris with Pierre Monteux, completed many recordings. One of the most widely circulated is a set of Beethoven's symphonies made for Reader's Digest; it was apparently the first recording to follow Beethoven's metronome markings. In choosing this approach, Leibowitz was influenced by his friend and colleague Rudolf Kolisch. Leibowitz also completed many recordings as part of Reader's Digest's compilation albums.
Leibowitz, René. 1947 Schoenberg et son école: l'étape contemporaine du langage musical. [Paris]: J.B. Janin. (English edition, as Schoenberg and His School: The Contemporary Stage in the Language of Music. Translated by Dika Newlin. New York: Philosophocal Library, 1949).
—. 1948. Qu’est-ce que la musique de douze sons? Le Concerto pour neuf instruments, op. 24, d’Anton Webern. Liège: Éditions Dynamo.
—. 1949. Introduction à la musique de douze sons. Les variations pour orchestre op. 31, d'Arnold Schoenberg. Paris: L'Arche.
—. 1950a. L'artiste et sa conscience: esquisse d'une dialectique de la conscience artistique. Préf. de Jean-Paul Sartre. Paris: L'Arche.
—. 1950b. Scènes de la vie musicale américaine. Liège: Éditions Dynamo.
—. 1950c. Arnold Schoenberg ou Sisyphe dans la musique contemporaine. Liège: Éditions Dynamo.
—. 1951. L'évolution de la musique, de Bach à Schoenberg. Paris: Éditions Corrêa.
—. 1957. Histoire de l'opéra. Paris: Buchet Chastel.
—. 1969. Schoenberg. Paris: Éditions du Seuil.
—. 1971. Le compositeur et son double: essais sur l'interprétation musicale. Paris: Gallimard. (Ed. augm., version définitive. Paris: Gallimard, 1986.)
—. 1972. Les fantômes de l'opéra: essais sur le théâtre lyrique. Paris: Gallimard.