Born in
Pisa, Galli started his career with his home town's youth side as a
midfielder before switching to the role of goalkeeper. He began his professional career with
ACF Fiorentina in 1977, where he played for nine
Serie A seasons. In
1986–87, he joined fellow league side
A.C. Milan, being first-choice for three of his four years, and establishing himself as one of Italy's best goalkeepers, winning the Serie A title and the
Supercoppa Italiana during his first season. He also started in both of the club's back-to-back
European Cup conquests, in
1989 and
1990, also winning consecutive
European Supercups in 1989 and 1990, and the
Intercontinental Cup in
1989. He also reached the final of the
1989–90 Coppa Italia with Milan. In his final season with the club, he was often alternated and faced competition for a starting spot from back-up
Andrea Pazzagli, whom manager
Arrigo Sacchi often fielded during league games, while Galli played in European matches. In the 1990 summer, following Milan's signing of
Sebastiano Rossi, 32-year-old Galli left, going on to represent
S.S.C. Napoli and appearing in an average of 33 league games during his three-year spell, starting by
winning the
Italian Supercup, 5–1 against
Juventus. In 1993, he played as the starting keeper for
Torino Calcio for a
single season, reaching the semi-finals of the
Coppa Italia, and the quarter-finals of the
Cup Winners' Cup, despite a disappointing mid-table finish. He finished his stint in the top division at the end of the
1994–95 season, after being named backup goalkeeper behind
Luca Bucci at
AC Parma, who won the
UEFA Cup that season, and reached the
Coppa Italia final, also placing third in Serie A. Galli retired in 1996 at the age of 38 after a brief stint with
A.S. Lucchese-Libertas of
Serie B. ==International career==