Born in Palmares Paulista, São Paulo, Matheus played in the youth teams at Cruzeiro and Ponte Preta. In January 2014 he agreed to a deal with Italian Serie A side Udinese from Ponte Preta's under-17 squad.[3] He was later assigned to Granada CF, a club in the same ownership group as Udinese in Giampaolo Pozzo, joining their reserve team in November 2014 but could only be registered the following January after he turned 18.[4] Matheus made his senior debut on 15 March 2015, playing the last 12 minutes in a 0–1 Segunda División B away loss against Arroyo CP. His first goal came on 4 October 2015, as he scored the opener in a 1–1 home draw against Mérida AD.
On 27 April 2017, Matheus joined fellow third division side Lorca FC on loan for two months, as an injury replacement to Chumbi,[5] helping the team win promotion to the Segunda División via the playoffs for the first time in the team's history.[6]
In July 2017, now owned by Watford, another club of the Pozzo ownership family, Matheus returned to the Spanish third division on loan with CF Fuenlabrada.[7]
On 22 August 2018, Matheus agreed to a one-year loan deal with fellow third division CD Mirandés,[9] achieving promotion at the end of the 2018–19 season. His loan was renewed for a further season as the team entered LaLiga 2.[10] He made his professional debut on 17 August, starting in a 2–2 away draw against Rayo Vallecano.[11] During the team's run to the 2019–20 Copa del Rey semi-finals, Matheus finished as the competition's second-highest scorer behind Alexander Isak and became the first player in a decade to score against four different La Liga opponents for a team in a lower division after netting against RC Celta de Vigo, Sevilla FC, Villarreal CF and Real Sociedad. Only Lionel Messi and Luis Suárez had done so in that time.[12][13]
Orlando City
On 21 August 2020, Matheus signed a two-and-a-half-year deal with MLS side Orlando City SC.[14] After a two-month delay, Matheus was eventually able to make his debut on October 24 as a stoppage-time substitute in a 2–1 defeat to Inter Miami.[15] He scored his first goal for the club in the following game, a 4–1 rivalry win against Atlanta United.[16]
Having only played for a combined 31 minutes for Orlando City, Matheus returned to the Spanish Segunda División on loan with Real Oviedo on 4 July 2021 ahead of the 2021–22 season with an option to buy.[17] He made his Oviedo debut on 20 August 2021, as a 67th-minute substitute in a 2–1 defeat to Almería.[18]
Racing Santander
On 8 July 2022, it was announced Aias had moved to newly-promoted Segunda División team Racing de Santander for an undisclosed transfer fee.[19] On 25 August 2023, Racing announced that his contract had been terminated by mutual agreement.[20]
^"Matheus Aiás chega para o ataque" [Matheus Aiás arrives for the attack]. Moreirense FC (in European Portuguese). 28 August 2023. Retrieved 28 August 2023.