Also in 2007 Mendler auditioned for Sonny with a Chance for the role of Sonny Munroe, but Demi Lovato was chosen.
In 2008, it was announced that Mendler would play the role of Kristen Gregory in the film adaption of the popular teen novel series The Clique by Lisi Harrison.
In the third season, Disney Channel announced that the series would feature a same-sex couple.
This decision caused a protest from the conservative group "One Million Moms" asking Disney Channel not to air the episode.
Mendler was featured on two singles released from the soundtrack of Lemonade Mouth, with both charting on the US Billboard Hot 100.
In 2004, she began her career in the animated Indian film The Legend of Buddha, later starring in the films Alice Upside Down (2007), The Clique (2008) and Labor Pains (2009) as a teenager.
In 2009, Mendler signed with Disney Channel and played Juliet van Heusen on Wizards of Waverly Place.
The film drew 2.1 million viewers, a better-than-average prime-time audience for ABC Family, and per the network, was the week's top cable film among coveted female demographic groups.
She had a supporting role in the film Alvin and the Chipmunks: The Squeakquel.