After his performance, Lilly D'Eramo (Nanni Eramo's wife) asked Claudio's mother to take him and his sisters to a specialized school.
He later acted in the TV play Vita col padre e con la madre with Paolo Stoppa, Rina Morelli and Corrado Pani.
During that time, Sorrentino started his career as a voice actor, dubbing a role in Italian in Delmer Daves' 1956 film The Last Wagon.
[3] Other actors he dubbed include Bruce Willis, Sylvester Stallone, Willem Dafoe, Ryan O'Neal, Ron Howard, Jeff Bridges, Mickey Rourke and many more.
In his animated roles, he voiced Dodger in the Italian dub of Oliver & Company, Gargamel in The Smurfs, and Mickey Mouse from 1978 to 1981.