(CNN) -- Once "the Special One," Jose Mourinho now calls himself "the Happy One" -- but his much-hyped first press conference back at Chelsea revealed that his new character may well be "the Stable One."
Nine years and a day after he was first unveiled at the English Premier League club as the brightest coaching talent in world football, Mourinho returned to London after what he described as the worst season of his career in Spain with Real Madrid.
He has signed a four-year contract, but has never lasted that long at any club he has managed despite winning multiple national titles and two European crowns.
"Yes. Now I am prepared for that because, to be fair, before I wasn't," the 50-year-old told some 250 gathered reporters Monday when asked if he was ready to stay for a long period.
"I was in a position to say which league I prefer, which one is the club I prefer, which one is the mentality I prefer.
"So now it's up to me to work hard and show my club that I deserve to be here for a long time. I have a contract for four years and I hope to go to the last day of that and if the club then wants to keep me, I'll be happy."
Although some key players remain at Stamford Bridge from his first reign, Chelsea has experienced a big turnover of staff since Mourinho left "by mutual consent" in 2007 -- having eight different managers in that time.
Three members of the club's coaching setup then are now managers at EPL clubs: Tottenham's Andre Villas-Boas, West Brom's Steve Clarke and Liverpool's Brendan Rodgers.
"I found a much better club in different areas, but there is stability needed in football terms," Mourinho said.
He insisted he did not fall out with Chelsea's billionaire Russian owner Roman Abramovich when he departed six years ago, and that they still have a good relationship.
"I read and I keep hearing that I was fired, I was sacked, we had a complete breakdown of our relationship -- that was not true," he said.
"Many didn't believe that but it was a mutual agreement. We thought it was best for both of us, for me and the club.
"Only because there was never a breakdown of the relationship is it possible for me to be here today. 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 we want, stability."
After leaving Chelsea, Mourinho won two Italian Serie A titles and the European Champions League with Inter Milan, which he described Monday as "probably the best moment of my career."
He refused to dwell on the controversies of his three years at Madrid, where he broke Barcelona's dominance by winning the La Liga title in 2011-12 with a record points and goal tally but failed to win over the local media after dropping World Cup-winning goalkeeper Iker Casillas.
"It was a football decision, I decided for one player and not the other and it is up to the player to accept it or not," Mourinho said. "All my decisions are based on meritocracy, then I can sleep well."
Mourinho was called the "scourge of Spanish football" by Barcelona's vice-president and was also criticized by players such as Andres Iniesta, having controversially poked his finger in the eye of coach Tito Vilanova and presided during some ugly, ill-tempered matches between the two teams.
"I 'damaged' Spanish football by being the manager who broke Barcelona dominance," he said.
"It looked like a dominance without an end but Real Madrid won the cup final against Barcelona, won the Super Cup against Barcelona, won in Barcelona and won the championship."
Real could not win a 10th European title, though Mourinho guided "Los Blancos" to three successive Champions League semifinals after several seasons of waiting to reach even the last eight.
He said Chelsea would not be fixated on winning the Champions League, having already done so for the first time last year.
"Chelsea focus on every competition -- I can't say one is more important than another one. In this moment the Champions League can't be an obsession for me. It's not an obsession for Chelsea. It's a consequence of our work."
Mourinho refused to criticize Chelsea's outgoing manager Rafael Benitez for his decision to sparingly use the club's longtime captain John Terry last season.
"I won't speak one word about Rafael Benitez's decisions, either on John Terry or any other player, all I can speak about is the future and the future is to meet John on July 1 and try to get the best out of him," said the Portuguese, who had a prickly relationship with the Spaniard when he was at Liverpool.
"I know what he can give, so let's try to make him again the best player he can be."
Just as Casillas was not guaranteed a place in his team, Mourinho said veteran stars such as Terry and Frank Lampard could expect no favors.
"It is important for me to tell you that there is no privilege for them. They know that already as they know my nature as a manger."
Mourinho had been linked with the managerial jobs at Manchester United and Manchester City, but David Moyes has replaced Alex Ferguson at Old Trafford and Manuel Pellegrini is expected to take over from Roberto Mancini.
"I am where I want to be. I wouldn't change it for anything," he said.
"I am the happy one. I am very happy. A lot of things happened in my professional life in the last nine years, but 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 my job, but I am a different person in this moment.
"If I have to describe myself, I would describe myself as a very happy person because it's the first time I arrive in a club where I already love the club."