George Clooney
Michael Clayton
Tom Wilkinson
Arthur Edens
Tilda Swinton
Karen Crowder
Michael O'Keefe
Barry Grissom
Sydney Pollack
Marty Bach
Danielle Skraastad
Bridget Klein (voice)
Wai Chan
Chinese Dealer
Alberto Vazquez
Player #1
Brian Koppelman
Player #2
Tom McCarthy
Waiter (voice)
Denis O'Hare
Mr. Greer
Julie White
Mrs. Greer
Austin Williams
Henry Clayton
Frank Wood
Gerald
Richard Hecht
Auctioneer
Bill Raymond
Gabe Zabel
Jonathan Walker
Del (voice)
Cynthia Mace
Wendy (voice)
Michael Countryman
Evan (voice)
Ken Howard
Don Jeffries
Amy Hargreaves
Interviewer
Susan Pellegrino
Secretary
Rachel Black
Maude
Matthew Detmer
Todd
John Douglas Thompson
Jail Guard
Merritt Wever
Anna
Brian Poteat
Deposition Lawyer
Christopher Mann
Lieutenant Elston
Edward Furs
Milwaukee Captain
Katherine Waterston
Third Year
John Gerard Franklin
Correction Officer
Remy Auberjonois
Fifth Year
Pun Bandhu
Fourth Year
Jason Strong
First Year
Robert Prescott
Mr. Verne
Paul Oquist
Starter
Terry Serpico
Mr. Iker
Heidi Armbruster
Anna's Sister
Pamela Gray
Cindy Bach
Andrew Hunter Sherman
U / North (voice)
Kevin Hagan
Raymond Clayton
Julia Gibson
Stephanie Clayton
Sean Cullen
Gene Clayton
Susan Egbert
Michelle
David Lansbury
Timmy Clayton
David Zayas
Detective Dalberto
Douglas McGrath
Jeff Gaffney
Gregory Dann
Cop
Cathy Diane Tomlin
Cop #2
Sam Gilroy
Copy Kid
Maggie Siff
Attorney #1
Sarah Nichols
Barry's Assistant
Susan McBrien
Jean
Jordan Lage
Partner
Neal Huff
First Associate
Paul Juhn
Second Associate
Patrick Askin
Auction Bidder (uncredited)
Angelo Bonsignore
Videographer (uncredited)
Kevin Cannon
Auction Worker (uncredited)
Clem Cheung
Landlord (uncredited)
Tony Gilroy
Taxi Driver (voice) (uncredited)
Emelie Jeffries
Raymond Clayton's Nurse (uncredited)
Josh Mowery
Lawyer (uncredited)
Kimmy Suzuki
Copy Shop Clerk (uncredited)
Steven Weisz
Executive (uncredited)