Mara's first ever appearance came on Law & Order back in 1997 for one episode, and she featured in numerous other shows as a guest star, but her reputation grew with a role in Brokeback Mountain (2005) and found herself involved in her most high-profile role as Shari Rothenberg on the cult series, 24. She appeared in the excellent fifth season as the Counter Terrorism Unit (CTU) analyst, and while it was only a five episode stint, the popularity of the show provided further exposure. This soon led to roles on Entourage and American Horror Story before landing her major part in the critically-acclaimed House Of Cards.