[7] Gerson made his senior debut on 22 February 2015, coming on as a second-half substitute in a 0–1 home loss against Vasco for the Campeonato Carioca championship.

On 9 June 2021, French club Olympique de Marseille announced that they reached an agreement in principle with Flamengo for the transfer of Gerson.

[14] Following a successful medical examination, he signed a five-year contract with the club, and was presented with the number 8 jersey on 1 July.

In November 2019 senior national team coach Tite stated that he was monitoring Gerson for a callup, having regretted not giving the player a call-up earlier that year.

In December, Gerson asked not to be called for Brazil under-23 team to the South American qualifying tournament for the Summer Olympics to be held in January, citing fatigue after an intense season with Flamengo.

In May 2021, Gerson was eventually summoned to the Brazil under-23 team for friendlies against Cape Verde and Serbia the following month, ahead of the 2020 Olympics.