Jerome Boateng was targeted by both Manchester United and PSG, however the 30-year-old decided to stay at the Allianz Arena with Bayern Munich.
Boateng, who has spent the last seven seasons at Bayern, told German tabloid 'Bild' about Mourinho's interest in bringing him to United.
"I had enquiries from Paris-Saint Germain and Manchester United, and I considered them," the former Manchester City defender told 'Bild'.
"Not because I wanted to leave Bayern Munich by all means. It was no escape, but rather the thrill of a new challenge. I feel completely contented at Bayern - one of the biggest clubs in the world.
"I phoned Jose Mourinho and told him that his interest honoured me and thanked him [for trying so hard to try and bring me to United].
"I explained to him my reasons for not joining.
"It's difficult to leave FC Bayern. Everything has to fall in place to top this club, if I do it. [Bayern Munich boss] Niko Kovac gave me the feeling that I am very important for him and the club."
Boateng has featured in both of Germany's UEFA Nations League matches, as the 2014 World Cup winners look to forget a disappointing summer.