The 31-year-old actress portrays ruthless and ambitious journalist Zoe Barnes on House of Cards, but tells the magazine she was "painfully shy" when she was young. She and sister Rooney started acting as teenagers, and Mara credits community theater shows and auditions for helping to break her out of her shell.
"I was very focused on a career and still am," Mara says. "I was never boy crazy."
"[Rooney and I] never had any kind of competitive thing between us, thank God," the actress adds. "We're really close."
House of Cards shocked fans in its second season premiere when Mara's character Zoe was killed by her lover, Frank Underwood (Kevin Spacey). The pair had begun an intimate relationship in the first season of the series, and the actress says that the show's numerous sex scenes came as no shock.
"I expected there might be a lot of nudity and edgy stuff required," Mara says. "Nothing shocked me. It just happened and it wasn't uncomfortable. From day two of working with Kevin [Spacey], I found him just as playful as I am."
The actress acknowledges that her family members "have a sense of humor" about her sex scenes "that they didn't used to have."
"By the time House of Cards came along, my family had death with plenty of other difficult things to watch with my career and my sister's career," Mara jokes.
Kate Mara will next appear in Transcendence on April 18. She is also slated to star as Sue Storm in the upcoming Fantastic Four reboot in 2015.