During the Revolutionary period in 1917-18, Mosolov worked in the office of the People's Commissioner for State Control, where he had fleeting personal contact with Lenin. He then served with the Red Army on the Polish and Ukrainian fronts and was wounded and shell-shocked.
From 1920 he worked as a pianist for silent films, and in 1922 entered the Moscow Conservatory to study under Reinhold Glière and Nikolai Myaskovsky, graduating in 1925. During his Conservatory years he composed several romances, four piano sonatas.
That year as his graduation, he joined the Moscow branch of the Association of Contemporary Music. He became director of chamber music for the Association of Contemporary Music, and then worked as a radio music editor.
In his prime (1926-28) his work was devoted to the ideas of the new, “modern” music, including constructivism. His music was often performed in Moscow. During those years his best works were composed and performed: Piano concerto no. 1 for small orchestra (1927), a symphonic episode “Factory. Music of machines” (1926-28); vocal pieces “Three children’s sketches” (1926), “Four newspaper announcements (1926). However many of Mosolov’s works were never performed in his life-time (e.g., the First String Quartet, a chamber opera “A Hero” (1928). Many of his early works were lost.
His works were often taken to embody the new brutalism and worship of the machine, and his most famous composition is the orchestral piece Iron Foundry (Zavod), a movement from a ballet entitled Steel (1927).
Later Mosolov fell foul of the musical politics of the USSR and after violent attacks on his reputation by Russian Association of Proletarian Musicians his works were suppressed from publication and performance. In 1936 Mosolov was expelled from the Union of Soviet Composers for 'public drunkenness'. He was sent to Armenia, Kirghizia, Turkmenia and Daghestan to document folksong (and also to 'compose a Turkmen Song about Stalin') before being arrested in 1937 for 'anti-Soviet propaganda' and condemned to eight years in the labour camps. Owing to the intervention of his former teachers he was released in a matter of months and lived on in poor health, still composing and working with folk music but largely denied a hearing by the authorities. Shortly after his death his music began to be revived.