Mourinho returns as 'the Happy One'
Mourinho dazzled the British press when he first joined the club in 2004, earning himself the tag of "The Special One" after describing himself as a "special" manager in his introductory press conference.
Around 250 reporters, photographers and television cameramen squeezed into a suite at Stamford Bridge in west London to witness his return but the 50-year-old Portuguese was careful to adopt a more mellow tone.
"Time flies," he said. "It looks like it was a couple of days ago, but it was nine years ago and since then lots of things have happened in my professional life.
"But I have the same nature. I'm the same person, I have the same heart. I have the same kind of emotions related to my passion for football and my job, but of course I am a different person.
"If I have to choose a nickname for this period, I would choose 'the Happy One', because I'm very happy. It's the first time I arrive at a club where I already love the club."
He added: "I want to be respected for what I did in the past, but I want to be loved for what I do from now."
Mourinho led Chelsea to back-to-back league titles during his first spell between 2004 and 2007, as well as two League Cups and one FA Cup, but left amid reports his relationship with club owner Roman Abramovich had soured.
But he maintained that those reports were false, instead saying that he left "by mutual agreement", albeit with a heavy heart.
Mourinho went on to manage at Inter Milan, where he won the 2010 Champions League, and latterly at Real Madrid, before signing a four-year deal at Chelsea earlier this month.
He was only able to return because his relationship with Abramovich had not broken down, he added.
"It's only because there was no break-up of relations that I'm here today," he said. "If we had real problems, I wouldn't be here.
"I think I'm back because we are in the best moments of our careers and ready to work together again. There are much better conditions at this time to succeed and have what the club wants, which is stability."
John Terry, Frank Lampard, Petr Cech and Ashley Cole all remain at Chelsea from Mourinho's first spell in charge but he warned them that "they don't have an advantage in terms of the other people (in the squad)".
However, he did suggest he was willing to rehabilitate the career of club captain Terry, who lost his place in the team under Mourinho's predecessor, interim coach Rafael Benitez.
"I know what he can give," Mourinho said. "Let's try to get the best out of him and try to make him a very important player, which he couldn't be last season."
Mourinho said he would look to make "a couple of signings" during the close-season transfer window, which he described as "correct practice", and said that Belgian forwards Romelu Lukaku and Kevin De Bruyne, who were loaned out last season, would both be reincorporated into the squad.
Mourinho returns to a very different Premier League landscape, with Alex Ferguson having notably been succeeded by David Moyes as manager of Manchester United.
"I'm still a bit disappointed that I'm back and I go to Old Trafford and Sir Alex is not there," he said.
"But David has the conditions and the experience and the protection of the club to do his job and do it well."
Despite the flux at the top of the Premier League, where 2011 champions Manchester City are also currently without a manager, Mourinho set some modest objectives for his first season.
"We go step by step," he said. "The first objective is the top four, the second objective is the top three, and the third is to be champion."
He also insisted he had no regrets about overlooked for the United job in favour of Moyes after Ferguson announced his retirement.
"I am where I want to be," he said. "I wouldn't change it for anything."