Sironi was born on 12 May 1885 in Sassari. In 1902 he enrolled in the engineering school at the University of Rome, but soon abandoned his studies. At the Scuola Libera del Nudo, which he began attending in 1903, Sironi met Balla, Boccioni, and Severini. He exhibited at the “Esposizione della Società degli Amatori e Cultori” in 1905, and contributed illustrations to the Socialist journal L’Avanti della Domenica. He travelled to Paris in 1906, Munich in 1908, and Frankfurt in 1910. Suffering from depression, he spent long periods of his youth in seclusion and destroyed most of his early, Divisionist work. He adhere to Futurism late in 1913, participating in the “Esposizione Libera Futurista” at the Galleria Sprovieri in 1914.

By 1915 Sironi had moved to Milan, where he took the place of Ardengo Soffici in the core Futurist group. That same year he signed the Futurist’ interventionist manifesto L’orgoglio italiano (Italian Pride). He served at the front with Marinetti, Boccioni, Russolo, and Antonio Sant’Elia. In 1919 Sironi participated in the “Grande Mostra Futurista” in Milan, organized by Marinetti as a show of the movement’s strength in the immediate post-war period. That same year he held his first one-man show at the Casa d’Arte Bragaglia in Rome. In 1920 he signed Contro tutti i ritorni in pittura (Against All Revivals in Painting) with Russolo and other former Futurists. From 1919-21 he painted his famous series of paesaggi urbani, urban landscapes, which transformed De Chirico’s haunting Italian piazze d’Italia, city-squares, into contemporary scenes of the Milanese industrial periphery.

In 1922 he was one of the founding members of the Sette di Novecento in Milan and became the leading exponent of the Novecento italiano. Sironi was the chief political caricaturist and illustrator for Mussolini’s official press, Il Popolo d’Italia (1927–33) and La Rivista Illustrata del Popolo d’Italia (1934–39). He was also the leading theorist and practitioner of mural painting and received prominent commissions from the regime. He authored the influential Manifesto of Mural Painting in 1933. After World War II he returned to easel painting in a style consistent with the abstract Informel movement. In 1956 he was elected member of the Accademia di San Luca. Sironi died in Milan on 13 August 1961.