San José won European Championships withSpain atunder-19 andunder-21 level. He made his senior international debut in 2014, and was a member of the squad at theUEFA Euro 2016 tournament.
In August 2007,Premier League clubLiverpool confirmed that the 18-year-old San José had joined on a three-year contract for a fee reported as €400,000.[5] He believed he had a greater chance of top-flight football viaLiverpool's reserves than by accepting what he saw as an unconvincing offer of bypassingAthletic's third team to play fortheir B team in theSegunda División B.[6] Over the next two seasons, he played regularly for Liverpool Reserves,[7] and helped them win the2007–08 Premier Reserve League title.[8] He frequently trained with the first team,[6] but the closest he came to playing for them was in February 2008 as an unusedsubstitute againstChelsea.[4]
In August 2009, San José returned to Athletic Bilbao on a season-long loan to gain more first-team experience.[9] He was given the number 12 shirt, and made his debut on 17 September 2009 in a 3–0 group stage home win againstAustria Wien in the2009–10 UEFA Europa League.[10][11] It was reported in early November 2009 that he was frustrated by the lack of first-team opportunities, and that if this did not improve he would look to shorten the loan agreement and move either back to Liverpool or on loan to another club in January 2010;[12] he finally made hisLa Liga debut on the 8th, playing the last two minutes of the 2–0 away win overRacing Santander,[13] and finishedthe campaign with 30 overall appearances, netting three times.[14][15][16]
In September 2019, San José reached the milestone of ten years with the same club.[10] On 24 November, he celebrated his 300th appearance in the Spanish top division in a 2–1 away victory againstOsasuna, breaking a 31–game undefeated streak of the hosts at theirEl Sadar Stadium.[28]
In July 2020, Athletic confirmed that San José's contract would not be extended beyond that summer, although the departure was delayed beyond its usual June expiry afterthe season was postponed due to theCOVID-19 pandemic in Spain. His contribution (along with long-serving colleagueBeñat Etxebarria, also leaving in similar circumstances)[29] was acknowledged at the last home fixture on 16 July 2020 in an empty San Mamés[30] – he was in the matchday squad but did not leave the bench,[31] with his last appearance four months earlier in theSpanish Cup semi-finals;[32][33] His team won that tie, but the circumstances of the delay and the end of his spell at the club meant he would have no opportunity to take part inthe final.
On 21 September 2020, San José signed a two-year deal with EnglishChampionship clubBirmingham City, whose head coach was fellow BasqueAitor Karanka.[34] He made his first-team debut, on 20 October away toNorwich City, in unfortunate circumstances: midfielderAdam Clayton was sent off after 86 goalless minutes, but before there was a stoppage in play to allow San José to come on, Norwich scored the winning goal.[35][36] He made what theBirmingham Mail dubbed an authoritative full debut playing in central midfield, looking "assured on the ball, intelligent off it",[37] and away toPreston North End a week later he "looked even more accomplished" in the centre of a back three before moving into midfield from where he crossed the ball forGary Gardner's winning goal.[38] As matches – and poor results – became more frequent, San José's level of performance dropped, he appeared to tire, mistakes appeared, and he lost his place in the matchday squad.[39][40][41] Under new head coachLee Bowyer, he seemed back to his best in a second-half cameo away toDerby County as Birmingham avoided relegation,[42] but on 28 May, his contract was terminated by mutual consent at his own request.[43]
On 8 July 2021, San José returned to Spain, signing a one-year deal with the newly promotedSegunda División clubAmorebieta.[44] He played 27 games as they were relegated, plus one in the cup, scoring once on 2 April to open a 3–1 home win overIbiza.[45] He announced his retirement from professional football on 14 August 2022.[46]
On 29 August 2014, San José was named byfull side managerVicente del Bosque in a 23-man squad for matches againstFrance andMacedonia in September.[48] He made his debut on 4 September, featuring the full 90 minutes in a 0–1friendly loss to the former,[49] and was subsequently selected for theUEFA Euro 2016 tournament alongside Athletic teammateAritz Aduriz.[50]