Her filmography includes roles in Traffic (2000), Swimfan (2002), The Banger Sisters (2002), The Perfect Score (2004), Flightplan (2005), How to Rob a Bank (2007), The Tortured (2010), and The Case for Christ (2017).

[9] 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.

[10] 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.

The following year, Christensen starred in three feature films: the teen thriller Swimfan,[16] the crime drama Home Room,[17] and the comedy The Banger Sisters.

[31] In 2009, she was part of the cast of the film adaptation of Veronika Decides to Die,[32] and starred in the romantic drama Mercy alongside James Caan and Dylan McDermott.

[34] Christensen was a regular cast member on the NBC drama television series Parenthood, which debuted on March 2, 2010, and concluded on January 29, 2015.

[37] In 2013, she starred in the musical film How Sweet It Is, directed by Brian Herzlinger,[38] and was a guest judge on 2 episodes of the cooking competition series Knife Fight.

[41] In February 2015, she was cast in the short-lived ABC crime drama series Wicked City as Betty Beaumontaine, a single mother who becomes romantically involved with a serial killer.

[45] Christensen next appeared as part of the all-star cast of HBO's courtroom drama film Confirmation, directed by Rick Famuyiwa and co-starring Kerry Washington, Wendell Pierce, and Greg Kinnear.

That same year, Christensen began starring as Ali Petrovich in the ABC drama series Ten Days in the Valley, alongside Kyra Sedgwick.

[49] She starred in Jon Abrahams' second film, the comedy mob thriller Clover, alongside Mark Webber, Julia Jones, and Ron Perlman.

[54] [55] On May 17, 2023, Christensen received the Mark of Excellence award at the Annual Medinova NY Dinner Gala, hosted by MC Ciano Joasil, a non-profit organization raising funds for hospitals in underserved areas of Haiti.