A native of Manaus, the capital of Amazonas, Santoro started to study violin and piano as a child. His efforts made the Government of Amazonas send him to study at the Conservatório Brasileiro de Música in Rio de Janeiro.
At the age of 18, he was already teaching violin at the conservatory. He was a pupil of Hans-Joachim Koellreutter, a composer who influenced him. He also studied in Paris with Nadia Boulanger. He co-founded and played in the Brazilian Symphony Orchestra. His prolific output was mostly instrumental and includes fourteen symphonies, three piano concertos and seven string quartets.
He was invited by the Government of the German Federal Republic for the Program "Resident Artist in West Berlin" (1966/67) and by the Brahms Foundation as Resident Artist of the Brahms House (Baden Baden).
His positions, titles and activities include being founder and principal of the Chamber Orchestra's of Radio MEC and the University of Brasília, the Symphonic Orchestra of the Radio Club of Brazil and the National Theater of Brasília; titular, Coordinating professor for of the Music Department of the University of Brasília; President of the Brasília Section of the Order of the Musicians of Brazil; Musical Director of the Cultural Foundation of the Federal District; member of the Managing Council of the Inter-American Music Council; organizer and director of the Center of Diffusion and Information for the music of Latin America together with the Institute of Comparative Studies of Music and Documentation (former West-Berlin); Member of the Brazilian Academy of Music, the Brazilian Academy of Arts and the Academy of Music and Letters of Brazil, of which he was President.
Between 1970 and 1978 he was Professor of Conducting and Composition, Director of the Orchestra and the Music Department of Heidelberg-Mannheim's State Superior Music School, in Germany. Orchestras he guest-conducted include the Philharmonic of Leningrad, Moscow State Orchestra, RIAS Berlin, ORTF Paris, OSSODRE Montevideo, Beethovenhalle Bonn, Symphonic of the Radio of Prague, Philharmonic of Bucharest, Symphonic of Orchestra of Porto, Philharmonic of Sofia, PRO ART (London) Île de France (Paris), Symphonic of the Leipzig Radio, Symphonic of Magdeburg, Philharmonic of Warsaw, as well as the main Brazilian orchestras.
- Stanley Sadie; Alison Latham (1994). The Grove Concise Dictionary of Music. London: Macmillan. ISBN 978-0-393-03753-1.