He joined Mussolini in Northern Italy after the latter's ousting and Italy's commitment to the Allies in World War II, becoming an official of the Nazi German-controlled Italian Social Republic (the "republic of Salò"). As finance minister, he also set up, in 1944, its infamous Brigate Nera paramilitary force. At the end of the war Pellegrini Giampietro was arrested and charged with collaborating with the enemy. On 28 August 1945 he was sentenced to thirty-year imprisonment for crimes against the State. He escaped from the prison and in 1949, he took refuge in Brazil, then Argentina, and finally Uruguay. He kept on working as a banker, and edited the magazine Sintesi.
