You probably know him from playing insensitive pseudo-boyfriend Adam Sackler opposite Lena Dunham's Hannah Horvath on HBO's new celebrated series, Girls, but you may not know that Adam Driver, 28, has had quite the career both on and off the screen.

Driver, a California native who also grew up in Indiana and an ex-marine, used to act in high school plays before he became serious about acting and transferred to Juilliard from the University of Indianapolis to study drama. Before his college years, however, and shortly after 9/11, Driver enrolled in the United States Marines Corps, where he was released on medical discharge after two-and-a-half years, just before being deployed to Iraq, for an injury he sustained to his sternum.

After graduating from Juilliard in 2009, Driver appeared in theater productions, both on and off Broadway, replacing Zachary Quinto in last year's production of Angels in America, according to Interview. Though a lot of Driver's acting credits have been on the stage, he's no stranger to nabbing highly coveted film roles — surprising for someone with such a relatively short career.

Driver has already appeared in the acclaimed 2010 HBO production about Jack Kevorkian, You Don't Know Jack, directed by Barry Levinson and also starring Al Pacino, John Goodman and Susan Sarandon, as well as in Clint Eastwood's recent biopic starring Leonardo DiCaprio, J. Edgar, and a larger role in the highly anticipated upcoming Lincoln, directed by Steven Spielberg and starring screen legends Daniel Day-Lewis, Tommy Lee Jones, David Strathairn and Sally Field.

Ironically, however, it is the HBO sleeper hit Girls that's making Driver a household name, a mere three years after he launched into serious acting. Though Driver didn't know Dunham and her project before he was cast, he has a great deal respect for his costar and the Girls creator. "It makes … sense to me to just play the character," Driver told Rolling Stone of Adam. "I very much trust Lena and what they come up with, though, of course when we work on the scenes, that feels very collaborative."

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