She began her career with supporting roles in the teen comedy films Big Fat Liar (2002) and She's the Man (2006).

[citation needed] At age 19, she had a job as a delivery driver for Big Wangs in Hollywood.

[6] She also guest-starred in Buffy the Vampire Slayer, Charmed, CSI: Crime Scene Investigation, Dawson's Creek, JAG, Medium, Psych, and Undeclared.

[citation needed] In 2002, she appeared in the film Big Fat Liar, starring Frankie Muniz, as Jason Shepherd's older sister Janie.

Breckenridge also guest-starred in the episode "With Friends Like Steve's" of American Dad!, also created by MacFarlane.

In addition, she returned for two episodes in season three of the series, Coven, as Kaylee, a young witch who excels in pyrokinesis.

[15] In 2015, she co-starred in the psychological thriller Dark from executive producer Joe Dante and director Nick Basile.

[16] In 2017, Breckenridge appeared in the recurring role of Sophie, Kate's childhood friend and Kevin's ex-wife, in the first season of the NBC drama series This Is Us.

[22][23] Since 2019, Breckenridge has played lead character Melinda "Mel" Monroe, a nurse-midwife who moves to a small northern California town following a personal tragedy, in the Netflix series Virgin River.