Aligi Sassu was born in Milan, In 1925, with his family now in financial straits, he was forced to leave school. At first he worked as an apprentice at “La Pressa”, a lithographic workshop; the following year that of a mural decorator's aide; at the same time, attending evening classes, he succeeded in concluding his studies. Together with his friend and futurist designer Bruno Munari, he introduced himself to Filippo Tommaso Marinetti, founder of Futurism. This meeting was fruitful: in 1928 he was invited by Marinetti to participate with his works at the Venice Biennale.
He studied Picasso, Diego Velázquez and the plastic nude. Of this period is The Last Supper, the painting that sums up the art of Aligi Sassu and, in the modern clothes of the characters and the urban setting, heralds what will be his future style.
In 1943 he illustrated the "Promessi sposi" of Manzoni with fifty-eight watercolors. He will present these tables later, in 1983, in the Manzoni house in Milan. In 1947, when he moved to the province of Varese, he worked hard to paint, in particular, Caffè, reminiscences of Paris, and sacred subjects.
Shortly thereafter he devoted himself to ceramics, producing about a hundred pieces. Returning in family city, in Sardinia in 1950, he drew inspiration from the landscapes that surrounded him and painted scenes of peasant and seafaring life.