Mourinho was still coaching Benfica when the possibility of replacing Roberto Martínez as Portugal coach emerged ahead of the World Cup.
The Portuguese Football Federation had previously considered Mourinho for the national team job, and discussions took place around the possibility of appointing him.
Instead, Real Madrid decided that Mourinho was the preferred choice for the club's next managerial change, with Pérez turning to a coach who had already led the team between 2010 and 2013.
Mourinho responded to the approach despite having other proposals available to him, particularly from the Portuguese national team.
The move followed months of contact between Mourinho and Pérez. Their relationship had continued after Mourinho left Real Madrid, with the club president retaining contact with his former coach.
The decision also followed a difficult period for Real Madrid, with Pérez and chief executive José Ángel Sánchez opting for another return to a manager who had previously worked at the club.
Mourinho left Benfica after Real Madrid activated his release clause, clearing the way for his return to the Santiago Bernabéu 12 years after his first departure.
Portugal subsequently turned to Jorge Jesus, who had extensive experience of working with Cristiano Ronaldo and was appointed as Martínez's replacement.
The opportunity for Mourinho to combine the Real Madrid role with the Portugal job was not without precedent.
In 2012, while Mourinho was still Real Madrid coach, the Portuguese federation approached him about taking charge of the national team while continuing in his club position.
Real Madrid rejected that proposal at the time, meaning Mourinho remained solely focused on his club responsibilities.
The latest approach therefore represented another opportunity for the Portuguese to take charge of his country's national side, but the timing coincided with Pérez's decision to bring him back to Madrid.
Mourinho had previously been considered for the Portugal position on several occasions, but the federation ultimately went in another direction.
The current return to Real Madrid also gives Mourinho the chance to lead the club again after his first spell ended in 2013, when he left after three seasons in charge.
His earlier tenure included a La Liga title in 2011-12, a Copa del Rey triumph and a Spanish Super Cup, while his return came after Pérez decided that a familiar figure was needed in the Madrid dugout.