Having launched, as an interpreter, the fundamental composers Geraldo Pereira and Luís Vieira, Roberto Paiva also was the first to record "Se Todos Fossem Iguais a Você" (Tom Jobim/Vinícius de Moraes) and several other compositions of the seminal de Moraes play Orfeu da Conceição, which inaugurated the partnership of the two composers and inspired Marcel Camus in his film Orfeu do Carnaval. The album was the LP with the soundtrack of the play and was released in 1956. Paiva's biggest hits (other than "Menino de Braçanã" by Luís Vieira), were with the Carnaval songs "O Trem Atrasou" (Paquito/Artur Vilarinho/Estanislau Silva) and "Marcha do Conselho" (Paquito/Romeu Gentil).
While still a teenager, Roberto Paiva won a novice contest at the Rádio Clube Fluminense (Niterói, Rio) and was hired soon afterwards to work at the Rádio Mayrink Veiga. Making friends with Nonô and Laurindo de Almeida, Paiva recorded in 1939 his first 78 rpm with "Último Samba" (de Almeida) and the valse "Jardim das Flores Raras" (Nonô/Francisco Mattoso). For the Carnaval of 1940, he revealed the sambista Geraldo Pereira recording one of his sambas for the first time with "Se Você Sair Chorando" (Pereira/Nelson Teixeira). He would later launch other songs by Pereira, such as "Lembras-te Daquela Zinha?," "Já Tenho Outra" (Ari Monteiro/Pereira), and "Brigaram Pra Valer" (Pereira/José Batista). He re-recorded "Pedro do Pedregulho" (recorded earlier by the composer) and by Roberto Martins, "Devagar com a Louça" (Martins/Oswaldo Santiago), "A Valsa dos Noivos" (Martins/Mário Rossi), and "Leva Meu Coração" (Martins/Mário Lago).
Moving to Rádio Educadora, Paiva recorded his first big Carnaval hit, the samba "O Trem Atrasou" (Paquito/Artur Vilarinho/Estanislau Silva). In 1949, he left the Educadora and spent one year touring Brazil. Upon his return, he joined the Rádio Guanabara, and in 1951, he went to Rádio Tupi. In 1952, he had another big hit in the Carnaval with "Marcha do Conselho" (Paquito/Romeu Gentil). In the same period, he had enormous success with "Menino de Braçanã," the song that launched Luís Vieira as a composer.