Age: 25
Occupation: Actress
Previous TIME 100 appearances: 0
For a young actress, Rooney Mara is sure making a big impression on the industry. Her first major role was playing Mark Zuckerberg's love interest in last year's hit The Social Network. Next, she'll star in a remake of the 1984 horror film A Nightmare on Elm Street. But her biggest break yet might end up being her portrayal of the socially awkward computer-hacking genius Lisbeth Salander in The Girl with the Dragon Tattoo, the first of three U.S. films being made based on Stieg Larsson's Millennium trilogy. Oh yeah: she also finds time to oversee the charity Faces of Kibera, which assists orphans in one of Africa's largest slums.