Santos was born in a working-class suburb of Sao Paulo in 1928. He started his cinema activities around 1952, in the first big studio built in Brazil, the Vera Cruz Studio. In 1956, Santos made his first movie, "O Grande Momento" ("The Great Moment"), the first neo-realistic movie made in Brazil. In 1965, Roberto Santos adapted a short novel by Guimaraes Rosa, "A Hora e Vez de Augusto Matraga" ("Matraga"), the only successful adaptation to cinema of a work by Guimaraes Rosa, the most important name in Brazilian literature in this century. The film was shown at the 1966 Cannes Film Festival.