She prepared for the role by working with two trainers seven hours a day for months, adding 15 pounds of muscle to her frame.

[13] In his review of the film, Rolling Stone's Peter Travers wrote: "Bosworth is a star in the making, but even she can't outshine the surfing footage, which is flat-out spectacular.

[11][18] In 2004, she played the lead role in romantic comedy Win a Date with Tad Hamilton!, opposite Topher Grace.

[25] The next year, she portrayed Chali, a Hare Krishna, in the film adaptation of Myla Goldberg's novel Bee Season (2005), about a dysfunctional Jewish family.

In a candid interview with Teen Vogue published in the August 2006 issue, Bosworth expressed her deep affection for the film and described the experience as a transformative period in her life, where she felt a newfound sense of self and completeness.

[34] Bosworth starred as Louise in the psychological drama The Girl in the Park with Sigourney Weaver, Alessandro Nivola and Keri Russell, written and directed by Pulitzer Prize winner David Auburn in his directorial debut.

"[37] Bosworth also filmed 21, an adaptation of the book Bringing Down the House, in early 2007 in Boston, Massachusetts and Las Vegas, Nevada,[38][39] reuniting with co-star Kevin Spacey and director Robert Luketic.

"[40] In 2006, she optioned the film rights to Catherine Hanrahan's novel Lost Girls and Love Hotels and was set to produce the project with filmmaker Nadia Connors.

"[44] In January 2008, Bosworth was named the new face of Calvin Klein Jeans and appeared in their ad campaigns.

[46] In 2011, Bosworth contracted to sing the television jingle for Cotton Incorporated's "Fabric of My Life" advertisement.

[48] Bosworth designed a jewelry line with friend and celebrity stylist Cher Coulter called JewelMint, which launched in October 2010.

[49] The first vertical venture of MySpace co-founder Josh Berman[50] and Diego Berdakin's social commerce company, BeachMint features designs by Coulter and Bosworth.

[59] In September 2018, Bosworth was announced as having the main role of KC on the Netflix science-fiction miniseries The I-Land.

[63] In late 2018, Bosworth and then husband Michael Polish debuted their privately funded film Nona,[64] which focuses on the issues of human trafficking.

[66] In 2018, Bosworth and Polish opened the Montana Institute of the Arts, a summer school for filmmaking students.

[70] In mid-2011, she began dating American director Michael Polish, whom she met earlier that year when he directed her in Big Sur.