Matheus Nunes was born on 27 August 1998 in Rio de Janeiro, Brazil, and moved to Ericeira, Portugal at the age of 12 with his mother and stepfather. He began his football career with local sixth-division club Ericeirense before signing with LigaPro side Estoril in 2018. His performances against Sporting CP in a cup fixture caught the eye of their scouts, and in January 2019 he joined Sporting for €500,000.
At Sporting, Nunes quickly established himself as a key figure under manager Ruben Amorim, contributing to a Primeira Liga title in 2020–21 and back-to-back Taça da Liga wins in 2021 and 2022. A notable early highlight came on 1 February 2021, when he scored an injury-time winner in a 1–0 derby victory over Benfica. His displays earned him the Primeira Liga Midfielder of the Month award for October and November 2021, and a place in the league's Team of the Year in 2021–22.
In August 2022 he moved to Wolverhampton Wanderers for a then club-record €45 million, before Manchester City paid £53 million to sign him in September 2023. He added a Premier League title (2023–24) and a FIFA Club World Cup (2023) to his honours at City.
A box-to-box midfielder capable of carrying the ball at pace and splitting defences with incisive passes, Nunes holds an important squad role at Manchester City. At international level, he opted to represent Portugal over Brazil and earned his first cap in October 2021, going on to appear at the 2022 FIFA World Cup and UEFA Euro 2024.