The departure of Thiago Silva and Zlatan Ibrahimovic have left the Rossoneri struggling with speculation continuing over Massimiliano Allegri's future at the club after Milan's worst start at home for over 80 years.
Netherlands international De Jong, who was brought to the club from Manchester City late in the transfer window, wants the fans to play an integral role in the team achieving results - starting with Anderlecht in the Champions League on Tuesday.
"I'm always optimistic and that's why I'm here. Milan is always Milan and we have to play to win and get results," the Dutchman told AS.
"Fans are our 12th man and they're important for us. I understand it's difficult to wait but the team is in the rebuilding process.
"To me it's not important about my own performance but the team's one and we have to learn by our mistakes. Tuesday we will play against Anderlecht and we have to win to start in the right way.
On the Serie A giants' shock loss to Atalanta on Saturday, De Jong remarked: "When you play against teams like Atalanta they become fearless, but we have to make the match ours.
"Anderlecht will be a tough match, if we win we will make the first step in the right direction."