Although the Italian team and the Finn parted ways in difficult circumstances at the end of the 2009 Formula 1 season, they put their issues behind them earlier this year after agreeing a deal to reunite from next season.
Di Montezemolo has been impressed with Raikkonen's attitude and expects the Finn will deliver a big boost to Fernando Alonso too.
"Kimi has been better than what I expected," said di Montezemolo during a lunch with media at Ferrari's Fiorano test track.
"He has been welcomed by the fans all over the world, he is far more popular with the fans, and that is important inside the team."
What Raikkonen has to do to succeed at Ferrari
Di Montezemolo has no concerns that the partnership will create any political tensions - and thinks that ultimately Alonso stands to benefit from Raikkonen's support.
"What about [the comments that] putting them together - Alonso and Raikkonen - could be dangerous?" said di Montezemolo.
"In F1 I accept the attitude to equalise everything, sometimes too much, but everything provides potential dangers.
"I think Fernando knows that he drives not for himself but for Ferrari, and Raikkonen knows that he is in the second half of his career, and [there are] two very important years for him in front. Experience, responsibilities."
RAIKKONEN 'A VERY CORRECT GUY'
The president expects Raikkonen to make a bigger difference to Ferrari's title prospects than predecessor Felipe Massa was able to in recent years.
"I think that the main reason why I am positive is because Kimi in particular in the races is very strong, so will be in condition to get points off even some of Fernando's competitors to get points for the team.
"And he is a very correct guy. Since he has been with us we have not got even one moment of problems.
"They are responsible and I think the presence of Kimi will be extremely important and useful to not leave Fernando alone at the front of the grid to fight from the first lap to the end.
"[Stefano] Domenicali has spoken very clear to both of them, and they have the honour and the responsibility to drive for Ferrari.
"Every driver while I have been here knows that he has to drive not for himself but for the team.
"If some driver wants to drive for himself there are many possibilities, they can do their own team, they can go in a different team, but in Ferrari these are the rules - and that is very clear."