Real Madrid have officially appointed Mourinho as head coach on a three-year contract
The 63-year-old takes over from Alvaro Arbeloa after Madrid endured a second successive campaign without a major trophy, trailing domestic rivals Barcelona.
"(Real Madrid have) agreed to appoint Jose Mourinho as the first team's head coach for the next three seasons, until June 30, 2029," said the 15-time European champions in a statement.
"Jose Mourinho will join Real Madrid on July 13th, the day pre-season begins."
One of football's most successful yet polarising managers, Mourinho arrives from Benfica, where the Lisbon club completed an unbeaten league campaign but finished third.
Benfica said on Wednesday that Real Madrid were paying 15 million euros for the Portuguese coach.
Mourinho managed Madrid between 2010 and 2013, winning LaLiga, the Copa del Rey and the Spanish Super Cup during an intense period of rivalry with Pep Guardiola's golden era Barcelona side.
Under Mourinho, Real Madrid became the first club to reach 100 points in a LaLiga season in the 2011/12 campaign, although Barcelona achieved the same the following season before Mourinho departed.
Mourinho divided the Real Madrid dressing room, with some players - including predecessor Arbeloa - fiercely loyal to him, while others were at loggerheads with the coach.
Known for ruling with an iron fist, Mourinho is tasked with keeping Real Madrid's dressing room egos in check, after multiple conflicts and problems marked a troubled season.
Madrid midfielder Fede Valverde was treated in hospital after a row with team-mate Aurelien Tchouameni in May, among other flashpoints.
Coaches Carlo Ancelotti, Xabi Alonso and Arbeloa also could not find a way to successfully deploy star players Vinicius Junior, Kylian Mbappe and Jude Bellingham together without destabilising the balance of the team.
In an appearance on Spanish television earlier in May, Madrid president Florentino Perez credited Mourinho with laying the groundwork for Real Madrid's last six Champions League titles, achieved in the years after the Portuguese departed.
The chief said he would bring back Mourinho if he were re-elected president earlier in June, which he was.
Mourinho back among European elite
Mourinho's return to Madrid also signifies a jump back to the European elite after several years away from the game's peak.
The coach burst into the limelight as he won the Champions League with Porto in 2004, before helping Chelsea claim back-to-back Premier League titles in 2005 and 2006.
Mourinho dubbed himself a "special one" as his team dominated the English top flight, before guiding Inter Milan to Champions League glory in 2010 as part of a unique treble for an Italian side.
Madrid chief Perez appointed him to try and stop Guardiola's powerful Barca team, which he achieved to an extent, in a fractious spell which also disrupted the harmony in the Spanish national team.
Mourinho returned to Chelsea, winning the Premier League in 2015, before modest spells at Manchester United, Tottenham and Roma, among other clubs.
He won the EFL Cup and Europa League with Manchester United in 2017 and, since then, has only lifted the Conference League trophy with Roma in 2022.
The coach was sacked by Turkish side Fenerbahce in August 2025 after failing to guide them past Benfica in a Champions League qualification play-off, before he was appointed by the Portuguese side the following month.