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.[9] After again appearing rarely, he subsequently left the club and joined Capivariano.
Atlético Goianiense
On 26 May 2015, Marllon moved to Atlético Goianiense, also in the second level.[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.