A statement on Parma's website said 30-year-old Cassano had joined for an undisclosed fee, while widespread media reports said he had signed a three-year deal.
"All the details of the operation that brought him here will be laid out tomorrow, Thursday July 4, at his presentation at the Tardini stadium," the club said.
Cassano, who has had a colourful career marked by tantrums and personality clashes, has played 35 times for Italy, scoring 10 goals. He featured at Euro 2012 but has been left out of their World Cup qualifiers since then.
He was dropped by then Inter coach Andrea Stramaccioni in March after a dressing room row, while he is also remembered for saying at Euro 2012 that he hoped there were no homosexuals in the Italy team, a comment for which he later apologised.
He had been expected to join Parma as part of a deal that took fellow striker Ishak Belfodil to Inter but there was no confirmation of that element of the transfer.
Cassano, who has played for both Milan clubs having left AC for Inter last August, will wear his favourite number 99 jersey.
The player's agent, Giuseppe Bozzo, said on Tuesday that Parma president Tommaso Ghirardi had already defined the signing as "the biggest of my time in charge of the Gialloblu (yellow and blue)".
