Cassini obtained her first film roles by 1970, appearing in The Divorce (1970) and playing her first lead role in Piero Vivarelli's Il dio serpente the same year. She had roles in films such as Pulp (1972) and Starcrash (1978) before reaching a great success in the commedia sexy all'italiana genre; a series of films starring Lino Banfi between 1979 and 1980, namely L'insegnante balla. . . con tutta la classe (1979), L'infermiera nella corsia dei militari (1979), and La dottoressa ci sta col colonnello (1980).