During the 1920s, Fedin belonged to a literary group called the Serapion Brothers, the members of which accepted the Revolution but demanded freedom for art and literature. His first novel, Goroda i gody (1924; “Cities and Years”), based partly on his experiences as an internee in Germany during World War I, was a social-psychological study of the reaction of the intelligentsia to the Russian Revolution. Gradually, however, he took a position more consistent with official Soviet literary policies and, in 1959, was appointed first secretary of the steering committee of the Union of Soviet Writers, a post he held until 1971, when he was elected chairman of the executive board.

His major work is generally considered to be the trilogy composed of Pervyye radosti (1945; First Joys), Neobyknovennoye leto (1947–48; An Unusual Summer), and Kostyor (1961–65; The Conflagration). Though they are Socialist Realist works, they are nonetheless fresh and vital and are free from the simplistic psychological portrayals that abound in many Soviet novels.