Signori was born in Alzano Lombardo, Bergamo. As a youngster he played in the youth system of Internazionale, but was eventually released after being told by the club that he was too short to succeed as a professional. He went on to make his pro debut for Leffe (1984–86), followed by Piacenza (1986–87 and 1988–89), Trento (1987–88), Foggia (1989–92), Lazio (1992–97), Sampdoria (January–June 1998) and Bologna (1998–2004). He then spent two short periods abroad: first in Greece in 2004 with Iraklis Thessaloniki; and then in October 2005 he signed a one-year contract with Hungarian team MFC Sopron to end his professional career.