Born in Planura, Minas Gerais,[1] João Marcelo represented Monte Azul, Barretos and Atlético Tubarão before joining Tanabi in 2023.
He made his senior debut with the latter in the year's Campeonato Paulista Segunda Divisão, featuring in five matches.
[2] He made his debut with the main squad on 17 November, coming on as a second-half substitute for Heitor in a 2–1 Série B away loss to Brusque, as both sides were already relegated.
[3] João Marcelo returned to the under-20s for the 2025 Copa São Paulo de Futebol Júnior, and scored five goals during the competition before being definitely promoted to the main squad.
[4] He scored his first senior goal on 26 January, netting Guarani's second in a 2–0 Campeonato Paulista home win over Noroeste.