[1] Born in Sant Joan Despí, Barcelona, Catalonia, Maffeo had youth spells at Espanyol and Manchester City, alongside his brother Pablo, before joining Wigan Athletic in 2015.
[2] On 29 August 2017, Maffeo made his professional debut at the age of 16, during Wigan's EFL Trophy tie against Blackpool.
After an unsuccessful spell at Hércules the previous season, Maffeo joined Andorran side Sant Julià on a season-long loan.
After an impressive display in Atlètic d'Escaldes‘ Champions League preliminary round tie against Budućnost Podgorica, Maffeo caught the attention of Manchego Ciudad Real, who would sign him on 14 July 2023.
Before the start of the league campaign, Maffeo would suffer an ACL injury in a friendly against Fuenlabrada, ruling him out for the rest of the season.