David Strathairn will play William Seward, the outspoken abolitionist who was Abraham Lincoln's secretary of state in DreamWorks Studios' "Lincoln," the studio said Monday.
Steven Spielberg is directing the movie, which stars Daniel Day-Lewis as the nation's 16th president and Sally Field as his wife, Mary Todd Lincoln.
The movie is based on historian Doris Kearns Goodwin's bestselling biography, "Team of Rivals." Tony Kushner wrote the screenplay.
Strathairn won an Emmy for HBO's "Temple Grandin" and was nominated for an Academy Award for "Good Night and Good Luck."
He stars in the upcoming "The Whistleblower," opposite Rachel Weisz and co-starred opposite Matt Damon in "The Bourne Ultimatum."
"Lincoln" begins filming this fall in Virginia. It is expected to be released through Disney's Touchstone in the fourth quarter of 2012.
Spielberg and Kathleen Kennedy are producing.