Born in San Giovanni Lupatoto (Veneto), Moschin graduated from the Accademia Nazionale di Arte Drammatica Silvio D'Amico and then began his career in the 1950s as a theatre actor, first with the Teatro Stabile in Genoa and then with the Piccolo Teatro di Milano in Milan. In the same period Moschin also began to appear in feature films and on television.
In his film career Moschin alternated character roles and, more rarely, leading roles, such as in Seven Times Seven and Caliber 9. His most famous role is that of Rambaldo Melandri in the Amici miei film series (1975–1985). He won two Nastro d'Argento Awards for Best Supporting Actor, in 1967 for Pietro Germi's The Birds, the Bees and the Italians and in 1986 for Nanni Loy's Amici miei – Atto III. Moschin is also well known for the role of Don Fanucci in Francis Ford Coppola's The Godfather Part II.
Gastone Moschin was married to Marzia Ubaldi since 1970, he had 1 daughter (Emanuela Moschin). He died in the hospital on 4 September 2017 from Kidney Failure. He was 88.
