Pettis won her first major role in 2006 when she was cast as Peyton Kelly, the long-lost daughter of Dwayne Johnson's quarterback character, in the 2007 Disney film The Game Plan. In 2007 Pettis was cast as Bailey Bryant, the sister of Corbin Bleu's character, in the 2008 film Free Style. In 2008, she had a small role in Dr. Seuss' Horton Hears a Who!, and had a role in A Muppets Christmas: Letters to Santa. She also had a small role as Lorena in the 2008 Will Smith film Seven Pounds. Pettis starred in the 2008 direct-to-video film Mostly Ghostly: Who Let the Ghosts Out?, and its 2014 sequel Mostly Ghostly: Have You Met My Ghoulfriend?, playing the role of ghost Tara Roland.