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