Kate Rooney Mara ( MAIR-ə; born February 27, 1983) is an American actress. She is known for her roles as reporter Zoe Barnes in the Netflix political drama House of Cards (2013–2014; 2016), computer analyst Shari Rothenberg in the Fox thriller series 24 (2006) and Ben Harmon's vengeful mistress Hayden McClaine in the FX horror miniseries American Horror Story: Murder House (2011).

She made her film debut in 1999 with Random Hearts. She has since appeared in Brokeback Mountain (2005), We Are Marshall (2006), Shooter (2007), Transsiberian (2008), Stone of Destiny (2008), The Open Road (2009), Transcendence (2014), The Martian (2015), Fantastic Four (2015), Morgan (2016), Megan Leavey (2017) and Chappaquiddick (2018), portraying Mary Jo Kopechne.