"Now we are back together at a great moment for both. We are to ready to marry again and to be happy and successful again," the Portuguese told Chelsea TV after the Premier League side announced their 'Special One' had signed a four-year contract.
"I feel myself not just a Chelsea manager, it's the first time in my career that I arrive at a club that I already love.
"I am happy and proud because when you return to a place it's for some reason, it's not because you had good results in the past, not just because the fans like you, it's because you left something here. I left something here," he said.
Mourinho, who left Real Madrid last weekend after three years in Spain, returns to a club where he won the 2005 and 2006 Premier League titles, as well an FA Cup and two League Cups between 2004 and 2007.
After falling out with Chelsea's billionaire owner Roman Abramovich, Mourinho moved on to Inter Milan, where he won a second Champions League after a first with Porto, and then to Real.
"Knowing these different football cultures, being in different countries, was important for my evolution as a manager and as a coach," he said.
Now he is back.
"I think I arrive in my club, my Chelsea, in the best moment of my career, my stability as a manager, my stability as a person," Mourinho said.
"I arrive in the best moment ready to give everything I have to try and make the club happy.
"I'm the same nature but much more mature with a different approach to things. Much more ready to establish myself in the club and stay for a long time."
Mourinho, who first joined Chelsea in 2004 and ended their 50-year wait for a top-flight title, said he would not live off past successes at the club.
"They (the fans) know I'm not coming here to sleep on the past and to be comfortable just because we have a great feeling and a great relationship," he said.
GROUND ZERO
"I'm very demanding with myself. I want to start from ground zero. I want to work hard again, to build a different team from the one I did in the past. I want to have that pressure on myself, like it was the first time I was here... make people feel they have a reason to be happy with me."
Rather than spend millions of pounds on big-money transfers, Mourinho said his priority was to "improve the team through work" before considering any potential signings.
"If I don't do that I'm not happy with myself. If after that we can improve the team by buying a couple of players it would of course be fantastic."
Mourinho should not have any trouble settling into the old routine, especially with "three, four, five players from the beginning of the winning Chelsea" still at the club from his first spell.
The Portuguese was referring to stalwarts like John Terry, Frank Lampard, Petr Cech and Ashley Cole, but added that he liked "the profile" of a squad who last season finished third in the Premier League and won the Europa League under interim manager Rafael Benitez.
"It's a young squad with a lot of young talent and I think they need stability to reach a higher point of their evolution. I hope I can give them that," the 50-year-old said.
"It will be good for me to work with them and good for them to work with me. Together we can all improve and make a better team."
The Premier League, Mourinho said, was still a "fantastic competition", despite no English team reaching the Champions League quarter-finals last season for the first time in 17 years, and was more competitive now than when he left six years ago.
"People say the level of the Premiership has gone down compared with other countries coming up but I don't believe that so much," he said.
"I believe we will have five or six teams that are very very strong. In my time here from 2004 it was more about us, Manchester United and Arsenal and after that there was a gap to the other teams.
"At this moment you can put a group of five or six teams aspiring to reach a Champions League spot and with more ambition to win the Premier League."
