She was born in Los Angeles, California to Jewish parents but became Christian at a young age. She initially was rejected from voice-acting classes around California and considered a career in the Air Force. However, a party she attended in her teen years led her to not give up her goal to become a legendary voice actress. She got classes and at age 25 in 1986 was picked up by Walt Disney Pictures & Hanna-Barbera Productions Incorporated for voice-acting. She provided back up character voices for Hanna-Barbera's & Disney's cartoons to start her career and worked her way to becoming promoted by bosses William Hanna and Joseph Barbera as a main voice actress. She split her time to working for both Disney and Hanna-Barbera since both animation organization bases were only a few miles apart in Los Angeles. She did the same for her career at Disney Pictures, working her way up to promotion, in the process befriending the Disney family.
In 1995, Bergman was diagnosed with bipolar disorder and become increasingly depressed. In 1996, she was brought to a hospital when she thought about committing suicide. She began improving her feelings and getting well in late 1995 and her family became closer to her. In 1998, she was hired by Nickelodeon to voice Timmy Turner in the Fairly OddParents shorts that aired on Oh Yeah! Cartoons (in the series itself, Tara Strong took over the role following Bergman's death).
In 1998, she voiced in Hanna-Barbera's Scooby-Doo on Zombie Island as Daphne Blake.
On November 11th 1999, Bergman went to a party celebrating Disneyland's 45th anniversary and then went back to her home in Los Angeles, California. When her husband and her best friend John Bell went to visit her that night, they came home and found Bergman dead. Bergman was buried in Los Angeles. As a result of the tragic death, the animation world mourned and started a charity in Bergman's name that studies how to prevent suicide in the future. As a replacement for her voices in Scooby-Doo's movie franchise and some of her Disney cartoons, was her life-long friend Grey DeLisle.
Her funeral was and still is one of the biggest known ceremonies in Disney History. Fellow animators and voice actors such as William Hanna, Joseph Barbera, Tara Strong, the Disney family, Grey DeLisle, Debi Derryberry, Tom Kenny, Dee Bradley Baker, Tom Hanks and many others attended the service.