[1][2] After the German occupation of Northern Italy during World War II, he joined and fought with the Italian Resistance in his home region of Liguria.

[1][2] After the war, De Negri became interested in films about social and political issues, "searching for an incisive, unprejudiced [...] artistically unpleasant cinema" to make.

[5][6] De Negri then created another cooperative, XXI Marzo Cinematografica, dedicated to the production of works by first-time directors.

[1][2] He first met Paolo and Vittorio Taviani in 1961, when they just had to halt the shooting of their first fiction feature film A Man for Burning (1962; co-directed with Valentino Orsini) due to a lack of funding, then helping them complete production.

"[1] De Negri received twice the David di Donatello for Best Producer for to his collaborations with the Taviani brothers, in 1983 for The Night of the Shooting Stars and in 1985 for Kaos, as well as the Nastro d'Argento for Best Screenplay for the former.