Stewart most recently portrayed rock star Joan Jett in The Runaways, a biopic of the titular band from writer-director Floria Sigismondi. Stewart met with Jett over the 2008–2009 New Year to prepare for the role, and ended up prerecording songs in a studio for the film. She received nearly unanimous praise for her performance. Josh Tyler of Cinema Blend pronounced her to be "a modern day James Dean. She gives the kind of performance in The Runaways that hasn’t been seen on screen since his death. The Runaways is her Rebel Without a Cause ... she’s absolutely brilliant as Joan Jett." The Metro Times wrote, "It turns out that Stewart is actually really good at capturing Jett's icy, tough-but-cool girl swagger, adding the needed touches of vulnerability that transform it into a pretty terrific performance... Stewart is a genuine rock star here." Also, A.O. Scott of The New York Times noted "Ms. Stewart, watchful and unassuming, gives the movie its spine and soul."
Stewart will star in a film called K-11 with Jason Mewes. The film, which is being directed by Stewart's mother, takes place in a dorm of the Los Angeles County Jail, and will feature Stewart as a male character. She has also been cast in the role of Mary Lou in an upcoming film adaptation of Jack Kerouac's cult classic novel On the Road. Shooting began in August 2010.
Stewart was listed as the highest earning female actress in Hollywood in the "2010's Top Hollywood Top Earners List" compiled by Vanity Fair. Throughout 2010, Stewart earned an estimated $28.5 million for all her movie appearances.