Paixão's first taste of professional football came in 2009 as he signed for Scottish Premier League club Hamilton Academical on 6 August, alongside twin brotherFlávio. He made his league debut late in the month, against Aberdeen. On 11 April 2011, it was announced that Paixão would leave at the end of the campaign. However, just three days later, he was released from his contract with immediate effect, alongside his sibling; he appeared in 56 official matches for the Accies, scoring six goals.
On 5 January 2012, Paixão joined his brother in Iran after signing with Naft Tehran F.C. until the end of the season. He made his debut in a 1–3 home loss against Foolad F.C. five days later, scoring his first goal in a 1–0 win over Malavan F.C. on 8 February.
Ethnikos / Poland
In the summer of 2012, Paixão joined Cypriot side Ethnikos Achna FC. He netted his first goal for his new club on 3 November, in a 1–1 draw at AEL Limassol. In June 2013, Paixão signed a two-year contract with Śląsk Wrocław in Poland. He scored a career-best 21 goals in 2013–14, but his team could only qualify for the relegation play-offs. In June 2015, Paixão put pen to paper to a two-year deal at AC Sparta Prague. The following January, after being barely used by the Czech club, he returned to the Ekstraklasa with Lechia Gdańsk after agreeing to a two-and-a-half-year contract; and his twin joined him a month later. Paixão concluded the 2016–17 season with hat-tricks in 4–0 home wins over Jagiellonia Białystok and Pogoń Szczecin. This brought his final tally to 18, joint with Lech Poznań's Marcin Robak as the top scorer. In March 2018, Paixão was removed from the first team when manager Piotr Stokowiec accused him of feigning an injury, and when his contract expired in June, he moved to Altay S.K. in the TFF First League. He was top scorer in his first season with the İzmir-based team, netting 29 times in 33 games.
International career
During their spell in Poland, both Paixão and his sibling were often poised to be called up to the Portuguese national team, but nothing came of it.
Personal life
Paixão's twin brother Flávio was also a footballer, Marco being the older by five minutes.