MTV approaches Cavallari, Lauren Conrad and a group of friends to document their lives in the affluent California beach town of Laguna Beach. The show, Laguna Beach: The Real Orange County, premieres in September 2004 to compete against FOX's teen drama The O.C. "It really was presented to us like a documentary," Conrad tells USA Today. "Nobody thought it was going to blow up like it did...definitely a different way to grow up." The MTV reality series turns Cavallari, Conrad and the boy they fought over, Stephen Colletti, into stars.
With Conrad and Colletti now in college, Cavallari becomes Laguna Beach's narrator in the show's second season. The high school reality series strikes a chord with MTV viewers, attracting a record 3.2 million viewers for the network.
Fellow Laguna star Talan Torriero introduces Cavallari to his friend Brody Jenner. The two begin dating, and Cavallari calls their love her "first mature relationship." She tells Teen People, "He's good-looking and he makes me laugh for hours." In August 2006, after about a year of dating, they call it quits.