[6] A product of Athletic Bilbao's youth system at Lezama, he made his debut with the first team in the 2003–04 season, becoming first-choice while often taking penalties and free kicks.

On 28 January 2007, he netted twice in a 2–0 away win over neighbours Real Sociedad,[12] who were finally relegated; Athletic narrowly avoided the drop, ranking in 17th position.

[16] 2012–13 marked the first year where Iraola failed to find the net in the league, but he continued to be the side's first-choice in his position as he featured in 35 games.

[20] On 16 June 2015, aged 33, Iraola moved abroad for the first time in his career, signing for Major League Soccer club New York City FC.

[24][25] On 20 August 2008, Iraola was called by new Spain coach Vicente del Bosque for a friendly with Denmark, alongside teammate Fernando Amorebieta.

[27] On 29 March 2011, after nearly one and a half years without playing for the national team, Iraola started in a 3–1 defeat of Lithuania in Kaunas for the UEFA Euro 2012 qualifiers.

[35] He took the team to the semi-finals of the Spanish Cup for the second time in their 92-year history, notably disposing of top-tier sides Celta, Sevilla and Villarreal.

[43] His first match in charge was a 1–1 home draw with West Ham United on 12 August, in which Dominic Solanke scored a late equaliser.