A product of Real Sociedad's youth system, he first appeared with the main squad on 7 November 1993, coming on as a substitute in a 1–3 home defeat against UE Lleida.

Subsequently, he became an essential element with the La Liga side, creating opportunities and scoring alike: in the 2002–03 season he contributed with 29 games and three goals as the Basques finished in second position, trailing eventual champions Real Madrid by only two points; in the subsequent edition of the UEFA Champions League, he scored a late consolation goal after coming on as a substitute in a 2–4 defeat away to Juventus FC.

[4] De Pedro joined Blackburn Rovers in mid-June 2004, after he had been refused a move to Southampton the previous year, playing out the remaining season of his contract undeterred.

[5] He made his debut for his new team on 14 August in a 1–1 Premier League home draw against West Bromwich Albion, before being replaced by Tugay Kerimoğlu for the second half of the match.

De Pedro started 2007–08, alongside former Real Sociedad and Spain teammate Agustín Aranzábal, with regional club CD Vera in the Canary Islands,[8] but was dismissed by the team's coach due to a lack of commitment.