In 1992, Stefanelli made her last film appearance in the drama Le amiche del cuore (Close Friends) directed by her then-husband Michele Placido.

The same year, Stefanelli landed her breakout role as the innocent Apollonia Vitelli-Corleone, the beautiful but doomed first wife of Michael Corleone (Al Pacino) in the American crime film The Godfather, directed by Francis Ford Coppola.

[6] In 1973, she posed nude in the Italian edition of Playboy,[7] but later refused a career in Hollywood, in order to avoid being typecast and required to do nudity.

She would later have roles in numerous Italian films, including Peccati in famiglia (Scandal in the Family), an erotic drama she starred opposite her husband Michele Placido.

[9] Having quit her acting career in 1992, Stefanelli owned and operated a fashion store in Rome called Simo Bloom, where she designed purses and shoes.