For players still playing, Crespo, Ronaldo, Seedorf have played for both AC Milan and Inter Milan.
The only player I can think of is Ronaldo
The player is the Italian footballer Filippo Izanagi.
No such player. Both Paul Ince and Robbie Keane have played for Liverpool and Inter Milan but no one has played for Liverpool and AC Milan.
I think it's Patrick Vieira
Ronaldo- PSV, Barcalona, Inter Milan, Real Madrid, AC Milan. Edgar Davids- inter Milan, juventus, ac milan, barcalona, ajax.
Clarence Seedorf moved from Inter to AC. Andrea Pirlo also played for Inter before being loaned out for 2 years before being sold to AC.