He became known for his investigative news stories, and incisive personality; Assis Chateaubriand nicknamed him "a víbora" (the viper).
He moved to Rio de Janeiro in 1937 to study Law,[2] but dropped out after the second year of college.
His first job was at the weekly newspaper Dom Casmurro, after that, Silveira was reporter and secretary of the leftist Diretrizes magazine, directed by Samuel Wainer, where he stayed until the magazine closure by Vargas' Department of Press and Propaganda (DIP), in 1944.
Silveira's stories "Eram Assim os Grã-Finos em São Paulo" ("That's How the Upper Class in São Paulo Was)" and "A Milésima Segunda Noite da Avenida Paulista" ("The Thousandth Second Night of Paulista Avenue") became classics of Brazilian journalism.
He also won the Líbero Badaró, Esso Especial, Jabuti and Golfinho de Ouro (Golden Dolphin) awards.