[2] Having missed the first part of the 2015 season due to international duty with Brazil U20, Marlon returned for the second half where he played as a starter for Fluminense.
[2] Marlon made his debut for the first team on 23 November 2016, in a Champions League group stage game against Celtic, coming on as a substitute in the 72nd minute for Gerard Piqué.
[9] On 16 August 2018, Marlon signed for Serie A club Sassuolo for an initial fee of €6 million with a buy-back clause in Barcelona's favour.
[2] Nevertheless, he impressed head coach Roberto De Zerbi who fielded him for 15 consecutive games as a starter without subbing him off.
[2] On 22 June 2021, Shakhtar Donetsk announced the signing of Marlon on a five-year contract,[12] where he reunited with former Sassuolo coach De Zerbi.
[16] Marlon represented Brazil internationally at the under-20 level at the 2015 FIFA U-20 World Cup, helping his side reach the final which they lost after extra time against Serbia.