The Portuguese rejoined the London outfit, with whom he won league titles in 2005 and 2006, in June after trophy-laden years spent in Italy and Spain with Inter Milan and Real Madrid. (Agencies)
He will take his title-chasing Chelsea side across London to face Arsenal, managed for the last 17 years by Arsene Wenger, on Monday (2000 GMT) where victory could send them level on points with leaders Liverpool.
"Realistically I hope at the end of those four years we sit, analyse the situation and that will be the point where we both - club and me - are happy to carry on or happy to separate," British media quoted Mourinho as saying of his contract on Monday.
"But I would like, say, 12 years. I'm 51 next month. I'd say 12 years, and then two to go to a World Cup with a national team. I would prefer the Portuguese national team. England second (choice)."
Mourinho has never completed four seasons with a club in his highly successful career that has brought seven league championships across Europe and two Champions League titles.
He left Porto after winning the Champions League in 2004 to join Chelsea where he left in September 2007, the start of his fourth season, following a breakdown of relations with the club and a falling out with billionaire owner Roman Abramovich.
He then joined Inter in 2008, lifting five trophies before departing to Spain in 2010 as he ended Barcelona's run of league championships before departing last May amid dressing room divisions.
He had been tipped to replace Alex Ferguson, who stepped down after 26 years at Manchester United in May, but Mourinho plumped for a return to Chelsea, where he remains revered for bringing them a first title in 50 years.
"There were a lot of teams (offered to me) who could be successful immediately in my hands," Mourinho said.
"I had Real Madrid. I left them because I wanted to, not because they wanted me to. I had other clubs in other countries where it would be easier to go and find an easy job immediately.
"If I was here for financial reasons, I wouldn't be here getting a lot less money than I had at Real Madrid, where I had three more years on my contract.
"I didn't come here because the job was easy, or because I had a team ready to attack the title, or because I was coming here for the best contract of my life.
"It's the worst of my last six years. I'm here because I love the club, I love the project. It's a different project."
The project involves tightening a leaky defence and finding a formula to attain more goals from his struggling strikers.
He also needs to help bring through a talented pool of youngsters to replace an ageing generation in John Terry, Ashley Cole and Frank Lampard - all key elements of his team during his first reign at Stamford Bridge.
The Portuguese said Chelsea would have a 'phenomenal team' next season with the arrival of some marquee signings to go along with his development of the current crop - if he is provided time.
Abramovich has employed seven permanent or interim managers in between Mourinho's two spells in charge, little wonder the Portuguese pushed for patience.
"The best way to (run a club) is to do it with stability. For the players, if you want to help them grow up, you do that much better with stability. In ideas, philosophy, model of play, style of leadership," he said.
"This all comes from stability at the highest level, with the owners and board and, after that, the manager.
"The second line of the hierarchy. That stability is very important. You look, for example, to Manchester United and everybody feels David (Moyes) will have his time to do his work in a calm way. I think that's fantastic," he said.
The Portuguese rejoined the London outfit, with whom he won league titles in 2005 and 2006, in June after trophy-laden years spent in Italy and Spain with Inter Milan and Real Madrid.