1997–2006: Beginnings
Christensen began her professional career with a supporting role in the comedy film Leave It to Beaver, and a one-episode guest appearance on the drama series Nothing Sacred, both of which were released/aired in 1997. She went on to guest star in numerous other television series in the late 1990s, including Frasier, The Practice, 3rd Rock from the Sun, and Touched by an Angel. She also starred in the Disney Channel original movie Can of Worms in 1999. Also in 1999, she starred as Abigail Winthrop on the short-lived CBS sitcom Thanks. That same year, she featured in Michael Jackson's music video for his song "Childhood", alongside actress Jena Malone.
For her performance as cocaine user Caroline Wakefield in Steven Soderbergh's crime drama film Traffic (2000), she received the awards for Breakthrough Female Performance at the MTV Movie Awards, Standout Performance – Female at the Young Hollywood Awards, and Outstanding Performance by a Cast in a Motion Picture at the Screen Actors Guild Awards. Also in 2000, Christensen guest starred in single episodes of Time of Your Life, Movie Stars, FreakyLinks, and The Pretender. In 2001, she had a recurring role on the sitcom The Geena Davis Show. She also appeared in an episode of the Fox sitcom That '70s Show, reuniting her with her Traffic co-star Topher Grace. She was named one of People's "Breakthrough Stars of 2001". The following year, Christensen starred in three feature films: the teen thriller Swimfan, the crime drama Home Room, and the comedy The Banger Sisters.
In 2003, Christensen starred in MTV's television film adaptation of Wuthering Heights, based on the Emily Brontë novel of the same name. She also recorded multiple songs for the film's soundtrack. In 2004, she starred in the teen heist film The Perfect Score, and the horror film Riding the Bullet. In 2005, Christensen recorded a version of "Let's Fall in Love" with John Stevens for his debut album Red. Also in 2005, Christensen co-starred in the films The Upside of Anger as Andy Wolfmeyer, co-starring Kevin Costner and Joan Allen; The Sisters as Irene Prior, with Maria Bello and Elizabeth Banks; and Flightplan as Fiona, starring Jodie Foster. The following year, she starred in the series Six Degrees, which debuted on the ABC fall schedule on September 21, 2006. Low ratings caused its cancellation after one season, leaving five episodes unaired.
