Before Heidi Mollenhauer performed the singing voice of Esmeralda in Disney's Notre Dame'ın kamburu (1996), she was a singer at a local night-bar. Heidi was then approached by Gary Trousdale and Kirk Wise, who were looking for someone to provide the singing voice for "Esmeralda." It was Heidi's first, and only, experience in voice acting.

Heidi also made a self appearance in the documentary The Making of Disney's 'The Hunchback of Notre Dame' (1996), alongside Tom Hulce and Demi Moore. Following this, Heidi literally disappeared from movies, theatre and television.