Moraes was born in Gávea, a suburb of Rio de Janeiro, to Clodoaldo da Silva Pereira Moraes, a public servant, and Lidia Cruz, a housewife and amateur pianist. In 1916, his family moved to Botafogo, where he attended Afrânio Peixoto Primary School. In 1920, he gained entrance to a Masonic lodge through his maternal grandfather. Fleeing the 18 of the Copacabana Fort revolt, his parents moved to Governador Island while Moraes remained at his grandfather's home in Botafogo to finish school. During visits with his parents on weekends and holidays, he became acquainted with the composer Bororo.