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.
Leaving Laguna behind, Cavallari moves to L.A. to pursue acting. "I would love to have a career like Cameron Diaz's," she tells PEOPLE, before making her acting debut on Veronica Mars. She also hosts UPN's short-lived, surprise-party series, Get This Party Started, and stars in music videos and TV shows (CSI: NY).
Cavallari quickly finds love again with former MTV personality and What I Like About You star Nick Zano. When they break it off at the end of 2007, the reality TV star gets Zano's initials removed from her left wrist.
With Lauren Conrad's departure from The Hills, Cavallari finds herself back in the spotlight. Joining Heidi Montag, Audrina Patridge and ex Brody Jenner, Cavallari promises to bring the drama as MTV's new star. "They want me to come in and stir up drama–and I'm good for it," admits Cavallari.
Cavallari brings the drama in the season 5, part 2 premiere of The Hills, fighting with Patridge and Stephanie Pratt – who says, "She's the girl that's going to stab us all in the back." In July 2010, she gives The Hills a surprise Hollywood ending that shocks fans. "We couldn’t have asked for a better ending," she tells PEOPLE.
While on vacation in Mexico, Cavallari, 24, is surprised with a marriage proposal from boyfriend Jay Cutler, whom she began dating last fall. "He surprised her with a quick trip to Cabo to ask her to marry him," a source tells PEOPLE of the Chicago Bears quarterback, 27. "I'm in love," the reality star previously gushed, "and it's been great."
Three months after getting engaged, Cavallari is reportedly "dumped" by Chicago Bears quarterback Jay Cutler, who calls off their engagement. "She's in shock that the dream wedding she was planning is going to end this way," a source tells PEOPLE of the bride-to-be, who was busy planning a spring wedding. "Jay Cutler was beyond controlling and didn't really like Kristin to go out," a friend of Cavallari said of their relationship. "I'm not surprised it didn't last."
With heartbreak behind her, Cavallari steps into the ballroom, signing up as a contestant on the thirteenth season of Dancing with the Stars. "I don't have any dance experience, so this is very new for me," Cavallari says of dancing with partner Mark Ballas. "I'm out of my element here. The only style of dance I would do is like bop around at a club."
BIOGRAPHY (top to bottom): amazon.com; Clark Samuels/Startraks; Everett; Barnsley/Symons/Pacific Coast News; MTV; Todd Williamson/WireImage; INF; Craig Sjodin/ABC