Joao Mario began his playing journey with local club AD Sanjoanense before joining the youth ranks at Porto as an eight-year-old.

Since then, he has spent his entire career with Porto, rising through the youth system to become a regular in their first team. He made his debut on 15 July, 2020, and went on to make 181 appearances for the club, scoring five times and assisting 25 more across all competitions.

He won nine trophies in Portugal between the league and cup competitions, and was part of the Porto side who won the UEFA Youth League in 2019. Internationally, he made his senior Portugal debut in November 2023 against Liechtenstein.