The Portuguese enjoyed a successful three-year stint with the Blues before leaving in 2007, but he has now returned to the club this summer.
Kalou believes that Mourinho possesses several unique characteristics that will help guide Chelsea to trophies during the upcoming season.
"We all know what Jose can do," Kalou told ESPN. "Jose can bring team spirit into a club and I think Chelsea at this moment need that.
"The only one who can bring this to Chelsea is Jose. I am happy that he is back because Chelsea did amazingly well to win all of the trophies they have done but the only one who can bring [success to the club again] is Jose. He is honest. As a coach, being honest is not always easy but he is able to gain the respect of all of his players because he is always honest. It doesn't matter if you're a big name or a small name.
"He also has a tactical mind which means he can bring change around during a game. Those are his key skills. I only spent one season with him but I learnt as much from him in one season as throughout my whole Chelsea career. I enjoyed all of [my coaches at Chelsea], and every one of them was different but I have to say Jose [was the best] as he brought me to the club. I learnt the basics with him and that has helped me every season since."
Mourinho signed Kalou for Chelsea in 2006.