A Friulian from Monfalcone, Guido Gratton played for Fiorentina in the 1950s, together with players such as Julinho, Virgili, and Montuori. During his time at the club, the team won the Serie A championship during the 1955–56 season, followed by 4 consecutive 2nd-place finishes; Fiorentina also reached the 1957 European Cup Final but lost to Real Madrid.