João Diogo Fonseca Ferreira, from Balasar in the Póvoa de Varzim area, began in the youth ranks of neighbouring Rio Ave before joining Benfica's academy as an under-14 in 2014. A right-back who can also play in the centre of defence, he made his senior bow for Benfica B on 11 August 2019.

Ferreira was promoted to the first-team squad and debuted in the Primeira Liga on 25 January 2021 against Nacional, going on to make a handful of senior appearances over the following eighteen months without securing a settled place.

With Alexander Bah signed in the summer of 2022 and Gilberto also on the books, Benfica loaned Ferreira to Rio Ave on 20 July 2022 for the 2022/23 season. He made eight league appearances there before the loan was cut short: on 7 January 2023 Benfica sold him to Championship club Watford, where he debuted on 14 January and scored against Rotherham United. He later had loan spells at Udinese and Braga before joining Saint-Étienne in August 2025.