Having started in music at eight, J. T. Meirelles studied composition and arranging at Berklee School of Music (Boston, Mass.). His professional debut was at 17 as João Donato's saxophonist. Next he moved to São Paulo, where he worked with Luís Loy. Returning to Rio in 1963 Meirelles formed the Copa 5, which debuted at the Bottle's Bar, at the Beco das Garrafas (Rio). In that same year he wrote the arrangement for the original recording of "Mas Que Nada," Jorge BenJor's first hit. From 1964 to 1975 he worked as an instrumentalist, conductor, arranger and producer at Odeon.