Walter Moreira Salles Júnior was born on 12 April 1956, in Rio de Janeiro. Salles resided in both France and the United States throughout his youth, following his diplomat father, Walter Moreira Salles. At the age of 15, Salles returned to Brazil, then under the dictatorship of Emílio Garrastazu Médici.
Salles attended the University of Southern California's School of Cinematic Arts.