Philip Seymour Hoffman as Truman Capote

Catherine Keener as Harper Lee

Clifton Collins Jr. as Perry Smith

Bruce Greenwood as Jack Dunphy

Bob Balaban as William Shawn

Mark Pellegrino as Dick Hickock

Marshall Bell as Warden Marshall Krutch

Amy Ryan as Marie Dewey

Bess Meyer as Linda Murchak

Chris Cooper as Alvin Dewey

Allie Mickelson as Laura Kinney

Craig Archibald as Christopher

Bronwen Coleman as Barbara

Kate Shindle as Rose

David Wilson Barnes as Grayson

Michael J. Burg as Williams

Kwesi Ameyaw as Porter

Andrew Farago as Car Rental Agent

Kelci Stephenson as Nancy Clutter

C. Ernst Harth as Lowell Lee Andrews

Kjartan Hewitt as Danny Burke

Nazariy Demkowicz as Paul Dewey

Ken Krotowich as Courthouse Guard

R.D. Reid as Roy Church

Rob McLaughlin as Harold Nye (as Robert McLaughlin)

Harry Nelken as Sheriff Walter Sanderson

Jon Ted Wynne as Journalist

Christopher Read as Journalist

Jonathan Barrett as Journalist

Edward Sutton as Old Man

John Warkentin as Warren Hotel Desk Clerk

Avery Tiplady as Alvin Dewey Jr.

John Destry as Pete Holt

Araby Lockhart as Dorothy Sanderson

John Maclaren as Judge Roland Tate

Olie Alto as Franklin Weeks

Adam Kimmel as Richard Avedon

Jeremy Dangerfield as Jury Foreman

David Rakoff as Ben Baron

Robert Huculak as NY Reporter

James Durham as Young Prison Guard

Will Woytowich as Cruiser

Wayne Nicklas as Row Guard

Jason Love as Row Guard

Norman Armour as Literary Enthusiast

Manfred Maretzki as Herb Clutter

Miriam Smith as Bonnie Clutter

Philip Lockwood as Kenyon Clutter

Marina Stephenson Kerr as Operator (voice)

Jim Shepard as Chaplain

Tiffany Lyndall-Knight as Gloria Guiness (uncredited)

Michelle Harrison as Babe Paley (uncredited)

Hedwig Herzog as Sophie Clutter (uncredited)