Born into a noble and wealthy family in Milan (one of the richest in northern Italy), Visconti's father Giuseppe Visconti di Modrone was the Duke of Grazzano, Visconti had six siblings. In his early years he was exposed to art, music and theatre, and met the composer Giacomo Puccini, the conductor Arturo Toscanini, and the writer Gabriele d'Annunzio. During World War II Visconti joined the Italian Communist Party.
Visconti made no secret of his homosexuality. His last partner was the Austrian actor Helmut Berger, who played Martin in The Damned. Berger also appeared in Visconti's Ludwig in 1972 and Conversation Piece in 1974 along with Burt Lancaster. Other lovers included Franco Zeffirelli.