Sergio Castellitto (born August 18, 1953) is an Italian actor, film director, and screenwriter.

Sergio Castellitto was born in Rome in 1953, to parents from Molise and Abruzzo, Southern Italy. After graduating from the Silvio D'Amico National Academy of Dramatic Art in 1978, he began his theatrical career in Italian public theater with Shakespeare's Measure for Measure at the Teatro di Roma and with roles in other plays such as La Madre by Brecht, Merchant of Venice, and Candelaio by Giordano Bruno. At the Teatro di Genova he starred in the roles of Tuzenbach in Chekhov's Three Sisters and Jean in Strindberg's Miss Julie, both under the direction of Otomar Krejka. In the coming years, he also starred in such theatrical productions as L'infelicità senza desideri and Piccoli equivoci at the Festival dei Due Mondi in Spoleto. He also appeared in Barefoot in the Park by Neil Simon. During his years in the theatre, he worked alongside many famous actors, including Luigi Squarzina, Aldo Trionfo, and Enzo Muzii.