In 2009, Banks appeared in the thriller The Uninvited, a remake of the Korean horror film A Tale of Two Sisters. The film was about an intrusive stepmother who makes life miserable for the teen daughters of her new husband. Banks based her character, Rachel, on Rebecca De Mornay's character in The Hand That Rocks the Cradle". "It was very important to me that every line reading I gave could be interpreted two ways," says Banks of her role, "So that when you go back through the movie you can see that".
Banks is a frequent co-star of actor Paul Rudd, the two having appeared in four films together to date (Wet Hot American Summer, The Baxter, The 40 Year Old Virgin, and Role Models). "There was a David O. Russell movie that I really wanted to make with Vince Vaughn that ended up falling apart", said Banks, referring to the film H-Man Cometh, in a January 2009 interview.
On December 8, 2009, it was announced that Banks would appear in at least four episodes of the Emmy-winning sitcom 30 Rock as a love interest for Jack Donaghy (Alec Baldwin). She went on to appear in nine episodes of the fourth season. Banks is set to star alongside Leslie Mann in What Was I Thinking?, based upon the book by Barbara Davilman and Liz Dubelman.
