Simplify the following text for a Grade 9 native English-speaking person.
Original: Demetrio Albertini ( born 23 August 1971 ) is a former professional Italian football midfielder who spent most of his career with AC Milan of the Italian Serie A , winning five national league championships and one UEFA Champions League title with that club .
Simplified: Demetrio Albertini ( born 23 August 1971 ) is a former Italian football player .