In 2009, Lynskey received strong reviews for "Away We Go", a comedy-drama directed by Sam Mendes in which she played a woman who has suffered a series of miscarriages. Wesley Morris of "The Boston Globe" called it "the best performance in the movie". Next, she co-starred as Matt Damon's wife in Steven Soderbergh's dark comedy "The Informant!". The film—which is based on real events—was described as "devilish fun" by "Rolling Stone", while Geoffrey Macnab wrote that Lynskey provided "sterling support" in his review for "The Independent". Soderbergh told "The Los Angeles Times", "She is so watchable. You never quite know what you're going to get, you just know it's going to be good. Her rhythms are really unusual, like her cadence and her reaction times to things, and the way she sort of lays out a sentence. It's just really, really interesting". Lynskey counts her time working on "The Informant!" as one of her favorite experiences. Also in 2009, she appeared as Edward Norton's pregnant fiancée in "Leaves of Grass", and as George Clooney's younger sister in "Up in the Air". The latter was nominated for Best Picture at the 82nd Academy Awards. The film's director, Jason Reitman, had never before cast a foreigner to play an American character, but Lynskey said that she "tricked" him into giving her the part by not speaking to him during her audition, therefore concealing her native accent. Reitman said he was "thrilled" by this. In October 2009, Lynskey was presented with a Spotlight Award at the Hollywood Film Festival. In 2010, she had a starring role in "Helena from the Wedding"; Jon Frosch of "The Hollywood Reporter" called it a "wise, luminous low-budget comedy", adding, "The actors form a seamless ensemble, but [the film] belongs to ... Lynskey". The following year, she received praise for her portrayal of Cindy—a recovering drug addict—in "Win Win", where she co-starred with Paul Giamatti. Writing for "Time", Mary Pols said, "[Lynskey] has become one of the most reliably intriguing supporting actresses in film ... she had small parts in "Away We Go", "The Informant!" and "Up in the Air" ... she was wonderful in all three.