Ayestarán was born in Beasain, Gipuzkoa, and had a short stint as a youth player at Real Sociedad. After starting his career as a fitness coach, he was appointed Rafael Benítez's assistant at Osasuna, and remained behind the manager at Extremadura, Tenerife, Valencia and Liverpool. On 1 September 2007, Ayestarán announced his departure from The Reds after 11 years partnering Benítez. Benítez accused Ayestarán of "betrayal" as Ayestarán "contacted other clubs behind his back" while Ayestarán rejected the accusations, claiming instead that Benítez "forgot his principles". Ayestarán joined Real Sociedad as sporting director in 2008, but left after a few weeks due to conflicts with the club president. He then served as fitness coach at Benfica and Valencia, leaving the latter in June 2010 for "professional reasons". In mid-2011, Ayestarán was named Quique Sánchez Flores' assistant at Al-Ahli Dubai, but left the club roughly a year later.
Manager
On 24 August 2013, Ayestarán took up coaching, being appointed at the helm of Estudiantes Tecos. On 29 May 2014, after failing to win promotion despite reaching the final of the tournament, Ayestarán announced his departure from Tecos, saying he had "no intention of continuing to manage in the Ascenso MX". On 26 August, he was appointed Maccabi Tel Aviv manager, replacing fellow Spaniard Óscar García. Ayestarán led Maccabi to a first ever treble in Israeli football, winning the Premier League, the State Cup and the Toto Cup. On 20 August 2015, however, he resigned from the club. On 20 August 2015, Ayestarán returned to Mexico, being appointed at the helm of Santos Laguna. On 21 November 2015, he and the club terminated his contract "upon mutual consent" after a 15th-place finish in the Apertura 2015. On 14 February 2016, it was announced that Ayestarán would join Gary Neville's backroom staff at Valencia. On 31 March, he was appointed manager of the club for the remainder of the season after the sacking of Neville. He suffered defeat against Las Palmas in his debut match before recording consecutive La Liga wins over Sevilla, Barcelona and Eibar in April. On 24 May 2016, Ayestarán was appointed Valencia manager until 30 June 2018. However, he was sacked on 20 September with the team in last place in the league table, having lost all four games of the season and 8 of his overall 12 fixtures. On 27 September 2017, Ayestarán replaced Manolo Márquez as the new UD Las Palmas manager. With Las Palmas, Ayestarán had 1 draw and 6 defeats and was sacked on 30 November 2017. On 29 May 2018, Ayestarán became manager of Pachuca in Liga MX. He was sacked on 20 January 2019, nine games into the season.
