The Portuguese boss has been officially unveiled at Stamford Bridge for a second spell with the west London outfit, describing himself as "very happy" at a club he already loves.
The Portuguese was confirmed as Rafael Benitez's successor last Tuesday, confirming one of the game's worst-kept secrets, and Mourinho says his return to the team he won two Premier League titles with was an easy decision due to his love for the club.
"I'm the happy one," he told reporters. "Time flies. It looks like it was a couple of days ago but it was nine years ago and since then a lot of things happened in my professional life. I have the same nature. I am the same person. I have the same heart. I have the same kind of emotions related to my passion for football and for my job. But I am, of course, a different person.
"In this moment if I have to describe myself, I describe myself as a very happy person and it is the first time I arrived at a club where I already love the club. Because before, I was arriving and I have to build emotional relation, and I honly (learn) how to love the club after some time there. This time is a new kind of feeling because this is the first time I am arriving to a club where I love it already."
Mourinho guided Chelsea to a first top-flight title success in his debut season in 2004-05, breaking a number of English football records in the process, including a 95-point haul and just 15 goals conceded.
The 50-year-old added a second title the following term, and ended up with six pieces of silverware before his departure in Sept. 2007. But he is now aiming to better that haul upon confirmation of his new four-year stay.
"In football you never know but I want to believe it's possible," he continued. "I always trust my work. In this case I know many of the people that belong to the club and I know the kind of mentality and ambition people have. My career was built and raised on success. I was able to reach success and win trophies and to let different kinds of legacy.
"So I have to believe on that and that's a normal message I want to go with my players which is work hard, work with quality. The club is much more important than ourselves. We are nobody compared with the club. And, of course, working well, normally success arrives."
Mourinho was sure to dismiss rumors regarding the sudden end to his first tenure, insisting the decision was mutual between himself and owner Roman Abramovich with no break down in relations.
The former Real Madrid and Inter manager does, though, feel the events of six years ago have paved the way for his return.
"That's not true," he replied when questioned on a tense relationship with Abramovich. "As a start, that's not true. I read and I keep listening that I was fired, I was sacked, we had a complete break up of relationships... that was not true. Many people didn't believe that but it was a mutual agreement. At the time we thought that was the best for both of us, for me and for the club.
"It was a sad moment. Of course it was a sad moment, but I don't regret that decision because after that I went to Inter, where I had probably the best moment of my career. And after that I went to Madrid, where we have still the record of the best team in Spanish history and for Chelsea things went well too."
Mourinho went on to say that his return would not be possible if he and Abramovic didn't have a relationship.
"It would be impossible for me to be here today if we had no relation, if we had real problems," he said. "And I think I'm back because we feel that we are in a moment of my professional life and in the case of the owner, also a moment of his career as an owner.
"I think we are in probably the best moments of our career if you can call it that and ready to work together again and in much better conditions this time to succeed and have what this club wants which is stability."