A self-taught composer, his first samba (with Zé Keti and Paulo Tiago), "Queixa," won fourth place at TV Excelsior's I FMPB (São Paulo, SP, 1965), interpreted by Ciro Monteiro. In 1966, Nara Leão pioneered, recording unknown sambistas (who would be famous) like him and Paulinho da Viola, Chico Buarque, and Jards Macalé on her Nara Pede Passagem. The first LP by Caetano Veloso and Gal Costa, Domingo, had his "Maria Joana."

In that year, Sidney joined a historic reunion at Sérgio Ricardo's home, where Gil and Caetano tried to convince him, Edu Lobo, Dori Caymmi, Chico Buarque, Francis Hime, Paulinho da Viola, Torquato Neto, and Capinam to join the Tropicalia movement. In 1967, his "A Estrada e o Violeiro" was awarded for Best Lyrics at TV Record's III FMPB, defended by Nara Leão and Miller. In the same year, he recorded his first LP, Sidney Miller (Elenco), which had "A Estrada e o Violeiro" (with Nara Leão), "Maria Joana," "Marré-de-Cy," "Argumento," "O Circo," "Menina da Agulha," and "Pede Passagem," among others.

Miller also wrote songs for the play Arena conta Tiradentes (Augusto Boal/Gianfrancesco Guarnieri), which also had music by Caetano Veloso and Gilberto Gil. The album was recorded by Nara Leão for the Cia. Brasileira de Discos in 1967 had "Maria Joana," "O Circo," and "Passa Passa Gavião." In 1968, he produced João de Barros' show Yes, nós Temos Braguinha, and Marlene's return show, Carnavália. That year, he also won first place at the Festival de Juiz de Fora MG, with "Sem Assunto" (recorded by two members of the future Quarteto em Cy, Cybele and Cylene). Also in 1968, he recorded his second LP for Elenco, Brasil, do Guarani ao Guaraná. Those were the Tropicalia times and this work is heavily Tropicalia-influenced, circumstance that made him later criticize this work. In 1969, he wrote the soundtrack of Paulo Tiago's film Senhores da Terra, took part in the show Alice no País do Divino Maravilhoso, produced Nara Leão's album Coisas Desse Mundo (Philips), and produced her show at the Sucata nightclub (Rio).

In 1971, he wrote the soundtrack for Haroldo Marinho Barbosa's movie Vida de Artista. The next year, he wrote music for the play Por Mares Nunca Dantes Navegados by Orlando Miranda. In 1973, he wrote the soundtrack of Ovelha Negra, a film by Haroldo Marinho Barbosa, and the music for the play A Torre em Concurso by Joaquim Manuel de Macedo. In 1974, he recorded the LP Línguas de Fogo (Som Livre), with "Cicatrizes," "Um dia Qualquer," "Línguas de Fogo," "Dos Anjos," "Alô," "Pala-Palavra," and others. The posthumous LP released by Funarte in the '80s (no date mentioned), Sidney Miller, brought "Maria Joana," "Nós os Foliões," "O Circo," "Menina da Agulha" (interpreted by Zé Luiz and Alaíde Costa), "Paisagem Sobre Valsa" (Alaíde Costa), "Pois é, Prá Quê?" (Zezé Gonzaga, Alaíde Costa, and Zé Luiz), and "A Estrada e o Violeiro" (Sidney Miller and Nara Leão).

Paulinho da Viola included "Nós, os Foliões" on his 1982 LP A Toda Hora Rola uma História. MPB-4 recorded "Pois é, pra Quê?" and "Meu Violão." Together, Quarteto em Cy and MPB-4 also recorded "A Estrada e o Violeiro." Sidney Miller has a song and his name cobbled into the sidewalk of Vila Isabel, Rio, together with Noel Rosa.