[2] On 21 January 2012, after returning from a failed loan at Duque de Caxias,[3] Marllon made his senior debut by starting in a 4–0 home routing of Bonsucesso for the Campeonato Carioca championship.

[4] He made his Série A debut on 7 June 2012, playing the full 90 minutes in a 2–2 away draw against Ponte Preta.

[5] Regularly used under Joel Santana, Marllon lost his space after the arrival of Dorival Júnior,[6] and subsequently served loans at Boavista[7] and Rio Claro,[8] where he failed to impress.

On 7 May 2014 he signed for Série B club Santa Cruz, after his contract with Flamengo expired.

[10] An undisputed starter during the 2016 season, he contributed with two goals and 36 appearances as his side achieved promotion to the top tier as champions.