Zaccardo has signed a three-and-a-half-year deal at the San Siro, while Rodney Strasser could also be part of the deal along with Mesbah going to the Ennio Tardini.
World Cup winner Zaccardo was delighted to make the move to Milan which will fuel rumours that Ignazio Abate could leave Milan for Zenit St Petersburg before the close of the window
"I am delighted and honored to be in a so important club and I will do everything to make my contribution," Zaccardo told the Milan Channel.
"I'm proud that Milan has interested in me. At age 31 I am here, after so many Serie A matches and I will give everything".
Parma general manager Pietro Leonardi confirmed Mesbah and Strasser were set to move to Parma as part of the Zaccardo deal.
"We are finalizing the exchange between Zaccardo and (Djamel) Mesbah with AC," said Leonardi. "Also could be included in the deal (AC Milan 23-year-midfielder, Rodney) Strasser, the negotiations are well underway."