At sixteen, she was discovered by a fashion photographer who helped her get work in commercials and other small parts, which eventually developed into a successful movie career. She is a spokesperson for Neutrogena and appears in print and television ads. She played the girlfriend of her husband's character "Terl" in the 2000 film Battlefield Earth, and received "Worst Supporting Actress" at the 21st Golden Raspberry Awards for her role in the film.

She was featured in the chart-topping Maroon 5 music video, "She Will Be Loved" in 2004. The video features a love triangle and romantic scenes between Preston and Maroon 5 frontman Adam Levine. In 2008 she was cast in a television pilot for a potential show called Suburban Shootout. She previously had a recurring role on Medium.