The actor and his wife welcomed their fifth child, a baby girl named Maeve Frances O'Donnell, on Dec. 10 in Los Angeles, reports People.
"Everyone's happy," says the actor's rep. "Mother and baby are doing great."
O'Donnell, 37, and his wife Caroline Fentreses, 35, have four other children: Lilly Ann, 8, Chistopher "Chip" Eugene, 7, Charles "Charlie" McHugh, 4, and Finley, 1.
The actor and Fentress, an elementary school teacher, met in college when he was her brother's roommate. They later married in 1997.
O'Donnell's film resume includes "School Ties," "Circle of Friends," "Batman Forever," "Batman & Robin," "Vertical Limit" and the upcoming "Kit Kittredge: An American Girl Mystery," based on the American Girl books and line of dolls.
Although he's best known for his big-screen work, he starred in the short-lived FOX legal comedy "Head Cases" and had a recurring guest role on ABC's top-rated medical dramedy "Grey's Anatomy."
In "The Company," he stars as Jack McCauliffe, a Yale grad recruited into the CIA in 1954, in "The Company," a miniseries based on Robert Littell's history of the CIA through the Cold War. The six-hour series, which also star Alfred Molina and Michael Keaton, premiered in August.