Angelo Ledda (3 episodes)

Self

Aaron Spencer (10 episodes)

Self - Guest (1 episode)

Piero Taruffi

Sheriff Eric Newlon

Self (1 episode)

Robert Philip

Tom Quincy (1 episode)

Dominic Morgan (18 episodes)

Producer

Harry Quebert (10 episodes)

(US version)

Self (1 episode)

Jack

Self (1 episode)

Self (1 episode)

Self (1 episode)

Self (1 episode)

Self (4 episodes)

Self

Tripp

Producer

Dylan

Dr. Harrison Copeland

Dr. Derek Shepherd (2 episodes)

Tom

(1 episode)

(1 episode)

Robert Philip

Self (1 episode)

Scott Casey

Self (1 episode)

Self - Guest (3 episodes)

Kenai (voice)

(1 episode)

Self (1 episode)

Self - Guest (1 episode)

Derek Shepherd (248 episodes)

Self (1 episode)

Dr. Paul Stewart (3 episodes)

Ben Weissman

(1 episode)

Peter Connor

Older Louis Masoudi

Andrew Hennings

(1 episode)

(1 episode)

Self (2 episodes)

(1 episode)

Cass (2 episodes)

Matthew (3 episodes)

(4 episodes)

Mark Kincaid

Fast Eddie

Jeremiah

The Stranger

Rodya Raskolnikov

Mike

Sam

Clayton

Jeffrey

Director

Floyd Gaylen

Pierre Arronax (2 episodes)

Harrison Burns (2 episodes)

Harrison Burns

Tom Harris

Tom

Jimbo Scott

Everett Calloway

Billy

John F. Kennedy (2 episodes)

Charlie Hunter

Robert Faldo

Self (1 episode)

Meyer Lansky

Charlie Farrow

Robert 'Bobby' Libner

The Plant (1 episode)

Chris Wooden

Randy Bodek

Michael

Potter Daventry

Associate Producer (1 episode)

Ellsworth "Sonny" Wisecarver

Ronald Miller

Rudy

Kellin Taylor

Mike Damone (7 episodes)

Underground Stuff Buyer (uncredited)

Corbet