Born in Brasília, son of former futsal player Mauro Brasília, Reinier joined the youth academy of Vasco da Gama in 2011. He moved to the Botafogo and Fluminense academies before joining Flamengo.[3]
Flamengo
Reinier made his senior team debut for Flamengo on 31 July 2019 in the second leg of Flamengo's Copa Libertadores tie against Emelec at Maracanã Stadium. Flamengo won 2–0 and advanced in the competition on penalty shootouts.[4] He made his league debut against Bahia the following weekend on 4 August.[5]
On 9 November 2019, Reinier extended his contract with Flamengo until 31 October 2024 with a release clause set at €35 million.[6][7]
Real Madrid
On 20 January 2020, Real Madrid CF announced that the club reached an agreement with Flamengo for the transfer of Reinier, who signed a contract until June 2026.[8][9] He was assigned to their reserves for the rest of the season. The fee was around €30 million.[10] On 7 March 2020, he scored his first goal for the Castilla against Coruxo.[11]
Loan to Borussia Dortmund
On 19 August 2020, Real Madrid announced that Reinier would be loaned to Borussia Dortmund until 30 June 2022.[12][13] On 27 February 2021, he scored his first goal for Borussia Dortmund in a 3–0 home win against Arminia Bielefeld.[14]
Loan to Girona
In August 2022, he was loaned to Girona on a season-long deal.[15][16] On 7 September 2022, he scored his first La Liga goal against Real Valladolid.[17]
Loan to Frosinone
On 1 September 2023, Reinier agreed on a loan deal to newly-promoted Italian Serie A club Frosinone until the end of the 2023–24 season. He finished the season with 22 appearances and 2 goals in the Serie A as well as one game and one goal in the Coppa Italia competition. Following Frosinone's relegation to the Serie B on the last matchday, Reinier once again returned to Madrid.[18][19]
Loan to Granada
On 30 August 2024, Reinier was loaned out to Granada on a season-long deal.[20][21]
