Stone's break came when she was cast as Martha in New Line Cinema's Secondhand Lions. She received a Young Artist Award nomination for her role in Secondhand Lions as well as a nomination for her 2005 guest appearance on House, M.D. She guest appeared on Line of Fire and Without a Trace. In February 2007, she joined the main cast of Disney's Wizards of Waverly Place as Harper. She has made YouTube videos with Wizards co-stars Selena Gomez and David Henrie, and created her own YouTube channel. In 2009, she had a voice role in the Disney Channel Original Movie Dadnapped. She also lent her voice to Phineas and Ferb as the voice of Amanda, Candace's daughter in the future in 2 episodes. In 2010, she played the main character in the film Harriet the Spy: Blog Wars. In 2011, she was in the film Mean Girls 2 playing Abby Hanover.
Jennifer is going to star in a new film which started production in April 2013 and ended in May 2013. It will be called "Good Girl" which she will also co-produce.
Jennifer is producing the new movie "Good Girl" which she also gets to star in. It started production in April 2013 and ended in May 2013.