Terry looked set to depart Stamford Bridge only a month ago but will now be preparing to face his former manager after accepting a one-year contract extension with the Blues.
After a protracted saga, Mourinho has replaced Louis van Gaal as United’s manager and Terry believes the Red Devils have appointed the right man to bring success back to Old Trafford.
“It’s fantastic news for Manchester United,” said Terry, speaking at the Horan and Rose charity dinner on Sunday.
“I’m sure that United’s fans and players will be delighted with that because, as I’ve said many times before, he’s the best manager I’ve worked under.
“It was unfortunate the way it ended at Chelsea this year but I wish him well because he’s also a great man. He’ll be great for Manchester United, I’m sure.
“The weather is slightly different maybe… but it’s a fantastic place to be and I’m sure he’ll settle in well with the likes of Ryan Giggs – hopefully he’ll stay and support him as well.”
Terry admits that he will find it unusual lining up against his former manager but expects the Portuguese to receive a warm welcome when he returns to Stamford Bridge.
“It’ll feel very different,” said Terry. “I’ve come up against Jose for various teams before so it will be interesting.
“He’ll get a great reception when he comes back to Stamford Bridge, for sure. First and foremost we have to look at ourselves this year and fight for the title.”
Chelsea will also have a new face in charge for next season after Antonio Conte was appointed Mourinho’s successor earlier this year.
Terry says he is excited to work with the experienced Italian and was pleased to resolve the uncertainty that surrounded his club future towards the end of a disappointing campaign last season.
“I’m delighted to sign another year,” he said. “It will be my 22nd year at Chelsea so I’m obviously delighted – I’ve been there an awfully long time.
“I’m looking forward to working under the new manager as well, it’s exciting times for all of us and hopefully we can improve on what was a disappointing season this year.
“At a big club like Chelsea, like all the other big clubs, you want to win trophies and be in competitions right until the last minute.
“This season we weren’t, so we have to learn from that and hopefully come back and be in the fight for a lot of trophies this year.”
Terry says he is already looking forward to the arrival of Conte and Mourinho, along with Manchester City manager Pep Guardiola, to the Premier League.
“I think it’s great for English football,” he said. “Not only what Leicester achieved last year with Claudio Ranieri coming in – Jose and Pep Guardiola up in Manchester, Conte coming to Chelsea. There’s real fight amongst the managers who’ll be eager to start well so I think it will be interesting times.”
The former England international, who won 78 caps for his country, backed Roy Hodgson’s side to impress at the European Championships in France this summer.
“I’ve just seen the boys and wished them well, they’re staying at my hotel,” he said. “I think they’ll do very well – the most important thing is to get a good start, get out the group.