Born Jennifer Jean von O? in Stamford, Connecticut, to Gloria and Frank von O?. She began her acting career as a child in regional stage productions and commercials. von O? made her television acting debut in 1986 on an episode of ABC Weekend Special, followed by a guest roles on Tales from the Darkside and Kate & Allie. From 1990 to 1991, she co-starred in the short-lived CBS sitcom Lenny.
From 1991 to 1995, von O? portrayed the role of Six LeMeure on the series Blossom. After the series ended, she attended film school at the University of Southern California for two years before dropping out to return to acting. In 1999, she won the role of Stevie van Lowe, Kim Parker's (Countess Vaughn) sidekick on The Parkers. During the run of The Parkers, von O? also provided the voice of Trinket St. Blaire in animated series Pepper Ann. After The Parkers ended its run in 2004, von O? appeared in the 2005 television film Marsha Potter Gets a Life. Later that year she guest starred on an episode of Cold Case, and parodied Lauren Graham's character of Lorelei Gilmore in the Family Guy episode "Perfect Castaway".
In addition to television, von O? has also appeared in the feature film Born on the Fourth of July (1989), opposite Tom Cruise. She has also provided the voices of Stacey in A Goofy Movie (1995) and Gracie in direct-to-DVD feature Dr. Dolittle 3 (2006).