After regional theater work, Giamatti made his film bow in Singles (1992) and later became a familiar supporting player in movies such as Private Parts and My Best Friend's Wedding (both 1997). His roles continued to grow in stature with Saving Private Ryan and The Truman Show (both 1998).
Giamatti's breakthrough leading role as artist Harvey Pekar in American Splendor (2003) earned kudos from critics, and the actor followed up with a bigger critical success portraying a depressed writer in 2004's Sideways. The next year brought him an Oscar nod for his supporting turn in Cinderella Man. In 2008, he won an Emmy and a Golden Globe for his role as the title character in the HBO miniseries "John Adams." Giamatti nabbed another Golden Globe Award in 2011 for Barney's Version.