This did not prevent him from getting a musical job, for he joined an orchestra as a violinist. He learned the art of conducting from observation and self-study and debuted as a conductor in 1908 at the Théâtre des Arts. He became friends with Debussy, who asked him to prepare the choruses for the premiere of Le martyr de St. Sébastien in 1911. After this, he became director of music at the Théâtre des Champs Élysées in 1913. In that position, he conducted the first French-language production of Mussorgsky's Boris Godunov.
He remained closely associated with theater music throughout his conducting career. Two major exceptions came in 1928 to 1932 when he led the Pas de Loup Concerts and after 1934, the year in which he founded the Orchestra National de la Radiodiffusion Française. This orchestra, whose name is sometimes given as the French Radio Orchestra or the O.R.F. (later O.R.T.F. Orchestra, is one of Paris' leading orchestras and the country's premier broadcast orchestra. He had two terms as its musical director, 1934 - 1944 and 1951 - 1958. His theatrical appointments included the Ballets Suédois (or Swedish Ballet, a French group despite its name) (1920 - 1923), the Opéra-Comique (1924 - 1925, 1932 - 1933), the Algiers Opera (1929 - 1930), and the Paris Opéra (1945 - 1950). Throughout his life, he was regarded as the primary champion of Debussy's opera Pélleas et Mélisande and his stereo recording of it taken as an authentic representation of the style of its original performances. He was also a prolific composer in a style similar to those of Debussy or late Fauré, with subtle, clear orchestration. His best-known composition is Le nursery (1905 - 1911), a five-volume piano suite that he also orchestrated. Read less