Mourinho paid the equivalent of €39 million to bring the Ghana international to Stamford Bridge in 2005, before bringing the 30-year-old to Spain on a season-long loan last summer.
Now, with the pair set to work together again in England, Essien claimed that the Portuguese's strong communication skills will be a crucial factor in helping to unite the Chelsea dressing room and the club as a whole once again.
"He's a lovely man," Essien said. "When you work with him and get close to him you understand the sort of person he is.
"He's very passionate about the game. He gives everything, he's very friendly, a very funny man. It's funny how people see him when he's giving interviews and stuff, but he's totally a lovely man.
"I think he's got something that most of the managers don't have. He's very close with his players, always trying to get the best out of his players, he knows how to talk to his players.
"He knows when you're not doing well - he tells you, so you do well the next game, or in the first half so in the second half you go back and keep fighting, but he's very close to his players and always talking to his players.
"When he used to be at Chelsea, the media was saying Chelsea are boring when we are playing, so if we can score most goals and get the most points and concede less, I don't know why they say we are boring.
"On the day we go out and win our games, and that's the most important thing."
Essien is preparing to host the Michael Essien Foundation's Game of Hope and Inspiration, which aims to create opportunities for underprivileged youth in the Awutu Breku area in Ghana in which he grew up.
The match will be played at the Accra Sports Stadium on June 8 and is set to feature a host of Chelsea and Real Madrid stars, including Cristiano Ronaldo, as an Africa XI and a World XI go head-to-head.
|Essien and friends | Ronaldo, Marcelo, and Mourinho star in the outtake trailer
For more information on the Game of Hope, visit the Michael Essien Foundation website or follow the Chelsea star on Twitter.