Matt Damon
as Will Hunting

Robin Williams
as Sean Maguire

Ben Affleck
as Chuckie Sullivan

Stellan Skarsgård
as Gerald Lambeau

Minnie Driver
as Skylar

Casey Affleck
as Morgan O'Mally

Cole Hauser
as Billy McBride

Vik Sahay
as MIT Student

John Mighton
as Tom

Rachel Majorowski
as Krystyn

Colleen McCauley
as Cathy

Matt Mercier
as Barbershop Quartet #1

Ralph St. George
as Barbershop Quartet #2

Rob Lynds
as Barbershop Quartet #3

Dan Washington
as Barbershop Quartet #4

Alison Folland
as MIT Student

Derrick Bridgeman
as MIT Student

Shannon Egleson
as Girl on Street

Rob Lyons
as Carmine Scarpaglia

Steven Kozlowski
as Carmine Friend #1

Jennifer Deathe
as Lydia

Scott William Winters
as Clark

Philip Williams
as Head Custodian

Patrick O'Donnell
as Assistant Custodian

Kevin Rushton
as Courtroom Guard

Jimmy Flynn
as Judge Malone

Joe Cannon
as Prosecutor

Ann Matacunas
as Court Officer

George Plimpton
as Psychologist

Francesco Clemente
as Hypnotist

Jessica Morton
as Bunker Hill Student

Barna Moricz
as Bunker Hill Student

Libby Geller
as Toy Store Cashier

Chas Lawther
as MIT Professor

Richard Fitzpatrick
as Timmy

Frank Nakashima
as Executive #1

Chris Britton
as Executive #2

David Eisner
as Executive #3

Bruce Hunter
as NSA Agent

Robert Talvano
as NSA Agent #2

James Allodi
as Security Guard

Michael Arthur
as Reunion Guest (uncredited)

Christian Harmony
as Student (uncredited)

Riva Di Paola
as MIT Student (uncredited)

Harmony Korine
as Hervé (uncredited)

Thomas Lundy
as Waiter (uncredited)

Paul McGillicuddy
as Race Track Fan (uncredited)

Daniel Olsen
as MIT Student (uncredited)

Stephen L'Heureux
as Bartender (uncredited)