Philip Seymour Hoffman
Truman Capote
Catherine Keener
Harper Lee
Clifton Collins Jr.
Perry Smith
Bruce Greenwood
Jack Dunphy
Bob Balaban
William Shawn
Mark Pellegrino
Dick Hickock
Marshall Bell
Warden Marshall Krutch
Amy Ryan
Marie Dewey
Bess Meyer
Linda Murchak
Chris Cooper
Alvin Dewey
Allie Mickelson
Laura Kinney
Craig Archibald
Christopher
Bronwen Coleman
Barbara
Kate Shindle
Rose
David Wilson Barnes
Grayson
Michael J. Burg
Williams
Kwesi Ameyaw
Porter
Andrew Farago
Car Rental Agent
Kelci Stephenson
Nancy Clutter
C. Ernst Harth
Lowell Lee Andrews
Kjartan Hewitt
Danny Burke
Nazariy Demkowicz
Paul Dewey
Ken Krotowich
Courthouse Guard
R.D. Reid
Roy Church
Rob McLaughlin
Harold Nye (as Robert McLaughlin)
Harry Nelken
Sheriff Walter Sanderson
Jon Ted Wynne
Journalist
Christopher Read
Journalist
Jonathan Barrett
Journalist
Edward Sutton
Old Man
John Warkentin
Warren Hotel Desk Clerk
Avery Tiplady
Alvin Dewey Jr.
John Destry
Pete Holt
Araby Lockhart
Dorothy Sanderson
John Maclaren
Judge Roland Tate
Olie Alto
Franklin Weeks
Adam Kimmel
Richard Avedon
Jeremy Dangerfield
Jury Foreman
David Rakoff
Ben Baron
Robert Huculak
NY Reporter
James Durham
Young Prison Guard
Will Woytowich
Cruiser
Wayne Nicklas
Row Guard
Jason Love
Row Guard
Norman Armour
Literary Enthusiast
Manfred Maretzki
Herb Clutter
Miriam Smith
Bonnie Clutter
Philip Lockwood
Kenyon Clutter
Marina Stephenson Kerr
Operator (voice)
Jim Shepard
Chaplain
Tiffany Lyndall-Knight
Gloria Guiness (uncredited)
Michelle Harrison
Babe Paley (uncredited)
Hedwig Herzog
Sophie Clutter (uncredited)