The Swede's position as a director has been questioned since the start of the this season.
But Dida told La Gazzetta dello Sport: "Zlatan represents Milan well. He knows everything about the club.
"Ibrahimovic never wants to lose. Thanks to his presence in the dressing room and as part of the staff, there is a guarantee that Milan will always aim to win."
Dida also commented on coach Paulo Fonseca: "Fonseca has just arrived and of course he needs time. He needs to work harder, because winning all the summer friendlies is different from playing in Serie A or the Champions League. We all have to be patient.
"He is a smart coach and he knows Italian football well. Working for Milan requires a little extra because they are more important than the clubs he coached before, and that can have an impact. However, it is important that he remains calm and continues to work with what he has in mind. With the confidence in his players, he can have an excellent season."