Petty graduated from North High School in Sioux City, Iowa in 1981 and worked for several years in Omaha as a graphic designer before pursuing acting.
The role that made Petty famous was playing Keanu Reeves' surfer girlfriend in the 1991 action thriller Point Break. Previous to that, she got her break starring with Richard Grieco in Fox's Booker.
In 1992, Petty was featured as 'Kit' in the box office hit A League of Their Own which starred Tom Hanks, Geena Davis and Madonna. Petty gained a starring role in Tank Girl in 1995, which made her into a cult icon. Her other films include Free Willy and In the Army Now. She also co-starred on a short-lived television series called Lush Life with her friend Karyn Parsons but it was cancelled after four episodes. Petty has also made marks in voicing "Livewire" on Warner Bros., Superman: The Animated Series, and Batman.
Although Petty was originally cast as Lt. Lenina Huxley in Demolition Man, disagreements over the character's direction led producer Joel Silver to recast the role with Sandra Bullock.
In addition she is the creator of the alternative clothing line "Lawd Knows", and is an accomplished artist. Lori is a vegan and has been for many years.