Mourinho had been approached to replace Carlos Queiroz, but Real blocked the approach and Paulo Bento eventually took full-time charge of the national side.
It was a development which the former Inter Milan and Chelsea boss described as his "greatest frustration of 2010".
"I believe that I will never coach a national team because it's a question of mentality, of personality," Mourinho told Portuguese media.
"I am a coach who works every day, is ready to play three times a week if necessary. But at that moment, I was motivated to do it."
Mourinho also praised compatriot and Real star Cristiano Ronaldo, describing the former Manchester United star as "extraordinary".
"He is fantastic, an extraordinary man," said Mourinho. "He is physically stronger than he has ever been. I believe that he is in the right condition to have his best season."
Real went into the winter break trailing great rivals Barcelona by two points in the Spanish title race, and Mourinho knows he is under pressure to deliver silverware as soon as possible.
"In all great institutions, the pressure is always huge. Ideally, I will stay until the end of my contract. But I know, and we all know, that I can't stay one, two or three years without winning a trophy," said Mourinho, who has a four-year deal.
"I have always known the rules of the game."