Born in Marxalenes, a neighborhood in Valencia, Sellés played for local side Parreta CF before finishing his formation with Burjassot.[2] At the age of 16, he was already coaching the youth sides of Parreta.[3] In 2002, after finishing his formation, Sellés entered the University of Valencia and became a coach of the university's football team; he led the club to a promotion from the Segunda Regional in their first senior season, and kept the club in the Primera Regional in the following campaigns.[2]
At the start of the 2008–09 season, Sellés joined a host of compatriots at Greek side Aris Thessaloniki,[4] being an assistant fitness coach.[2] He departed in 2009 to perform a similar role for the Juvenil squad of Villarreal.[5]
Sellés moved to Norwegian club Strømsgodset in 2015, working as Chief Data Analyst,[8] before returning to Azerbaijan as an assistant of Gurban Gurbanov at Qarabağ.[9] In July 2018, he joined Danish club Aarhus, assisting manager David Nielsen for two seasons.[8][10]
In July 2020, Sellés returned to his hometown after being appointed manager of Valencia's Juvenil B squad.[11] On 1 January 2021, he returned to Denmark and joined Copenhagen as assistant manager to Jess Thorup.[8]
Southampton
On 10 June 2022, Sellés departed Copenhagen to join Premier League club Southampton, as assistant to Ralph Hasenhüttl.[12] On 7 November, Hasenhüttl was sacked by Southampton, and Sellés was placed in caretaker charge of the club.[13] Sellés took charge of one match for The Saints before the appointment of new manager Nathan Jones, a 1–1 draw against Sheffield Wednesday in the EFL Cup on 9 November – in which Southampton advanced to the next round after a penalty shootout.[14]
He again took temporary charge of the team after Jones was sacked in February 2023.[15] His first game in charge was a 1–0 away victory over Chelsea.[16] On 24 February, Sellés was appointed manager until the end of the 2022–23 season.[17][18] On 24 May 2023, Southampton confirmed that they would not renew his contract when it expired at the end of the season.[19] On 28 May 2023, Sellés managed his final game at Southampton; a 4–4 draw against Liverpool on the final day of the 2022–23 Premier League season.[20] In his three months in charge, he oversaw the relegation of Southampton to the EFL Championship, having won just two games in 17 matches.[21]
Reading
On 26 June 2023, Reading announced an agreement with Sellés to become their new first team manager, subject to a successful work visa application.[22] On 14 July 2023, Reading confirmed the appointment of Spaniard as the club's first team manager after his visa application was successful.[23] His first professional game in charge was a 0–1 defeat to Peterborough; his first victory came in the following match when Reading beat Millwall 0–4 away in the EFL Cup.[24][25]
Hull City
On 6 December 2024, Sellés was announced as the new head coach of Hull City on a two-and-a-half year contract, with the option for a third.[1]