Justice has guest starred on several television series including Gilmore Girls and Everwood. She played "Rebecca" on The Suite Life of Zack & Cody in the episode "The Fairest of Them All". She had roles in the films Mary, When Do We Eat?, Silver Bells, The Garden, and Unknown.
Justice's first major role came in 2005 on the series Zoey 101. Her character (Lola Martinez) was a perky outgoing actress who eventually becomes best friends with other students, Zoey Brooks (Jamie Lynn Spears), Nicole Bristow (Alexa Nikolas), and Quinn Pensky (Erin Sanders). Also in 2005, Justice was on the cover of American Girl magazine's May and June issue. In 2009, Justice played Tammi Dyson in Nickelodeon's original movie, Spectacular!. She also had a supporting role in the feature film, The Kings of Appletown, starring Dylan and Cole Sprouse. Also in 2009, she guest starred on The Naked Brothers Band, in the iCarly episode "iFight Shelby Marx", and on True Jackson, VP. In 2010, Justice appeared in one episode of The Troop.