Christopher Walken
Secretary William Cleary
Rachel McAdams
Claire Cleary
Jane Seymour
Kathleen Cleary
Ellen Albertini Dow
Grandma Mary Cleary
Keir O'Donnell
Todd Cleary
Bradley Cooper
Zachary 'Sack' Lodge
Henry Gibson
Father O'Neil
Rebecca De Mornay
Mrs. Kroeger
Jennifer Alden
Christina Cleary
Kathryn Joosten
Chazz's Mom
Norma Michaels
Old Irish Woman
James Carville
Himself (uncredited)
Will Ferrell
Chazz Reinhold (uncredited)
John McCain
Himself (uncredited)
Lindsay Schoneweis
Woman in Hat (uncredited)
Kelsey Wedeen
Bridesmaid (uncredited)
Tanaya Nicole
Woman at Jewish Reception