His best-known work, in English speaking countries, is the anti-fascist novel Conversations in Sicily, for which he was jailed when it was published in 1941.

In many cases, separate editions of his novels and short stories from this period, such as The Red Carnation were not published until after World War II, due to fascist censorship.

In 1937, he was expelled from the National Fascist Party for writing in support of the Republican side in the Spanish Civil War.

The news of the events of the Hungarian Uprising deeply shook his convictions in Communism and made him decide to largely abandon writing,[citation needed] leaving unfinished work which was to be published in unedited form posthumously.

In 1959, he co-founded with Calvino Il Menabò, a cultural journal devoted to literature in the modern industrial age.