Born in the Madureira suburb, Jair do Cavaquinho frequented the Portela samba school beginning at the age of seven, taken by his mother and older sisters, who paraded at the Ala das Baianas. He taught himself to play an instrument he had built, it resembled a cavaquinho. In 1962, his first composition, "Barracão de Zinco," was recorded by Jamelão. In 1965, Do Cavaquinho participated in the two volumes of the LP A Voz do Morro. With Nelson Cavaquinho, he wrote "Vou Partir," "Eu e As Flores," and "Enquanto a Cidade Dorme," the latter recorded by Haroldo Santos. With Nelson Sargento, he wrote "Ela Deixou," recorded by Elizeth Cardoso on her Elizeth Sobe o Morro. Cardoso recorded on the same album another four compositions of his: "Pecadora," "Vou Partir," "Eu e As Flores," and "Meu Viver." In 1965, Do Cavaquinho participated with Paulinho da Viola, Elton Medeiros, Nelson Sargento, and Anescar do Salgueiro in the musical Rosa de Ouro, organized by Hermínio Bello de Carvalho, which relaunched Araci Cortes and introduced Clementina de Jesus. Do Cavaquinho also participated in the group Voz do Morro, with Zé Kéti, Oscar Bigode, José Cruz, Nelson Sargento, Paulinho da Viola, Anescar do Salgueiro, and Elton Medeiros; they recorded the LPs Roda de Samba, Vol. 1, which had his "Pecadora" (written with Joãozinho) and "Meu Viver" (written with Elton Medeiros/Kleber Santos), and Roda de Samba, Vol. 2. In 1967, his composition "E a Rosa Voltou" was recorded on the LP Rosa de Ouro, Vol. 2. Still in 1967, he participated in the group Os Cinco Crioulos. In 1969, his samba-enredo "Treze Naus" won the internal contest of Portela, having been presented by the school in the annual parade. In the '70s, he also participated, with composers of other samba schools, in the group Cinco Só. In 2000, Marquinhos de Oswaldo Cruz recorded "Enquanto a Cidade Dorme" on his CD Uma Geografia Popular. In 2001, Do Cavaquinho performed with Dauro do Salgueiro, Nei Lopes, Nelson Sargento, Dona Ivone Lara, Baianinho, Niltinho Tristeza, Casquinha, Zé Luiz, Nilton Campolino, Monarco, Elton Medeiros, Luiz Grande, Jurandir da Mangueira, and Aluízio Machado in a show and on the CD for it, Meninos do Rio, at the Banco do Brasil culture center, in Rio de Janeiro.