Before being the third goalkeeper at
A.C. Milan, he played for
Lodigiani (one season),
Lazio (six seasons),
Cagliari (three seasons),
Cesena,
Fiorentina and
Piacenza (1 season each). Though he made four appearances for
Italy's Under-21 squad, Fiori was never called up for the senior side. He has made only two official appearances in eight seasons with the club: a 4–2 loss in Serie A to Piacenza on 24 May 2003, and a 1–0
Coppa Italia win over
Sampdoria as a first-half injury replacement for
Christian Abbiati on 18 December 2003. After his retirement in 2008, Fiori became a goalkeeping coach at A.C. Milan until 2016. After a brief interlude with the Chinese side
Shenzhen, and then Spanish side
Deportivo La Coruña, a club coached by former teammate
Clarence Seedorf, Milan announced the return of Fiori as goalkeeper coach on 5 July 2018. In August 2020, he was appointed as
Napoli goalkeeper coach. ==Personal life==