Fábio Vieira was born on 30 May 2000 in Santa Maria da Feira, Portugal. Spotted at a regional tournament at the age of eight, he joined Porto's academy, coming through the ranks before making his Primeira Liga debut on 10 June 2020 against Marítimo. He became a regular fixture in Porto's senior squad from the 2020–21 season onward.
His most defining campaign at Porto came in 2021–22, when he recorded six goals and 14 assists in 27 league appearances, including a hat-trick of assists in a single match against Belenenses. That season Porto reclaimed the Primeira Liga title, with Vieira named the league's Midfielder of the Month for April 2022.
A creative, technically assured attacking midfielder, Vieira is known for his vision and ability to unlock defences with precise passing and goals from distance. Arsenal signed him in June 2022 for a reported fee of €35 million, and he marked his Premier League career with a goal from outside the box against Brentford in September of that year, going on to win the FA Community Shield in 2023.
At youth international level, Vieira was named in the Best XI of the 2019 UEFA European Under-19 Championship and won the Player of the Tournament award at the 2021 UEFA European Under-21 Championship, reaching the final on both occasions. He was included in Portugal's preliminary squad for the 2022 FIFA World Cup but did not make the final selection.
Vieira is currently registered with Arsenal.