In April 2009, Fox began filming Jonah Hex, in which she portrayed Leila, a gun-wielding beauty and Jonah Hex's (Josh Brolin) love interest. The film was released on June 18, 2010.Despite receiving top billing, Fox described her role in the film as being a cameo.Jonah Hex was a critical and commercial failure in the U.S., with its international distribution cancelled after its poor performance. The film was named the "worst picture of the year" by the Houston Film Critics Society.Fox next starred alongside Mickey Rourke in Passion Play. The film's poor reception at the Toronto Film festival led to its conventional theatrical distribution being bypassed for a direct-to-video release, with only two screens briefly showing the film to fulfill contractual obligations.Mickey Rourke remarked that Passion Play was "terrible. Another terrible movie." Fox was the voice of the Hawaiian Spinner Dolphins in the Na Nai'a Legend of the Dolphins, a 3D documentary film. The story is told by a cast including Kate Winslet, Ellen Page, Gerard Butler, James Franco, Julian Lennon, Diego Luna, Cheech Marin, Whoopi Goldberg, Isabella Rossellini and Daryl Hannah.
In March 2009, Variety reported that Fox was set to star as the lead role of Aspen Matthews in the film adaptation of the comic book Fathom which she will also co-produce with Brian Austin Green.Fox appeared with Dominic Monaghan in the music video for Eminem and Rihanna's single "Love the Way You Lie".
In 2012, she appeared briefly in Sacha Baron Cohen's comedy The Dictator and in a featured role Judd Apatow's comedy This Is 40. She was the voice of Lois Lane in the film Robot Chicken DC Comics Special, an episode of the television comedy series Robot Chicken, and it aired as a one-off special during Cartoon Network's Adult Swim on September 9, 2012.
In January 2013, Fox was featured in a Brazilian television commercial for Brahma beer. In February 2013, Fox set aside her differences with her former director Michael Bay when it was confirmed that she would work again with him on his upcoming reboot of Teenage Mutant Ninja Turtles.Prior to the beginning of filming, she colored her tresses red as to the portrayal of a red-headed April O'Neil's character. Photos of her at location set in New York City emerged in early May marked her first official day of filming, slated to be released on August 8, 2014.