Katie Holmes as Katie Burke

Benjamin Bratt as Wade Handler

Charlie Hunnam as Embry Larkin

Zooey Deschanel as Samantha Harper

Fred Ward as Bill Stayton

Mark Feuerstein as Robert Hanson

Melanie Lynskey as Mousy Julie

Philip Bosco as Professor Jergensen

Gabriel Mann as Harrison Hobart

Will McCormack as August

Gabrielle Union as Amanda Luttrell

Greg Kramer as Andre

Gillian Ferrabee as Susan

Barry Julien as Ted

Tony Goldwyn as David Schaffer

Scott Faulconbridge as Jed

Vanessa Petch as Young Katie

Victoria Petch as Young Katie

Kevin Ryder as Regular Guy

Rachelle Lefevre as Eager Beaver

Paul Lemelin as Eager Beaver

Simon Peacock as Tech Recruiter

Howard Bilerman as Venture Capitalist

Mark Camacho as Detective Rigney

Mike Tsar as Detective Kanter

Robert Burns as Archivist

Kim Lambert as Female Interviewee

Alicia Westelman as Girl Singer

Jodie Resther as Girl Singer

Bonnie Mak as Waitress

Joe Cobden as Student on Cell Phone

Kwasi Songui as Campus Security Officer

Jay Lavalley as Campus Security Officer

Arthur Holden as Frank Peabody

Brett Watson as Recovering Alcoholic College Student

Noel Burton as Bill

Bill Rowat as Harrison Hobart, Sr.

Liz MacRae as Mrs. Harrison Hobart

Richard McConomy as Cabbie

Bill Corday as Homeless Guy

Gianpaolo Venuta as Research Assistant

Sheena Larkin as Female Mogul

Ivan Smith as Professor

Mike Paterson as Russian Bear

Samir Mallal as Indian Guy

David Gow as Passerby Outside Plum

Tim Petch as Katie's Father

Ryan Wilner as Student in Cafeteria

Charles S. Doucet as Recovering Alcoholic Member

Charles Papasoff as Recovering Alcoholic Member

Andrea Sadler as Recovering Alcoholic Member

Christian Paul as Recovering Alcoholic Member

Shawn Baichoo as Trip Hop Inferno: Virgil

Ryan Kennedy as Trip Hop Inferno: Tortured Soul

Philip LeMaistre as Trip Hop Inferno: Tortured Soul

Giancarlo Caltabiano as Trip Hop Inferno: Dante

Joseph Baugniet as Trip Hop Inferno: Performer

John Fallon as Trip Hop Inferno: Mime

Daniel Lee as Trip Hop Inferno: Wolf

Malcolm Travis as Trip Hop Inferno: Minos

Bryanne Hastings as Trip Hop Inferno: Performer

Joan McBride as Library Assistant

Aaron Baril as Student Choir

David Benson as Student Choir

Chris Burrage as Student Choir

Jonathan Davis as Student Choir

Jon Day as Student Choir

Benjamin Kwong as Student Choir

Kris Epps as Student Choir

Owen Meyers as Student Choir

Nathaniel Misri as Student Choir

Dantonio Pisano as Student Choir

David Podgorski as Student Choir

Mark Barter as Student Choir

Mark Biunno as Student Choir

Padraig Buttner-Schnirer as Student Choir

Chris Forbes as Student Choir

Fred Issid as Student Choir

Andrew Mangal as Student Choir

Nick Roy as Student Choir

Jonathan Stewart as Student Choir

Si-Wai Francis Zih as Student Choir

Ahad Sianati as Student Choir

Raffael Cavaliere as Student Choir

Marika Anthony-Shaw as Student Choir

Annesley Black as Student Choir

Marie Claude Harvey as Student Choir

Amelia McMahon as Student Choir

Tobie Miller as Student Choir

Anne-Lise Nadeau as Student Choir

Julie Paquet as Student Choir

Martine Poirier as Student Choir

Fanny Quenneville as Student Choir

Sahra Ucar as Student Choir

Shannon Simpson as Student Choir

Wing-Chan "Emily" Chung as Student Choir

Marie-Noel Daignault as Student Choir

Nancy Duncan as Student Choir

Doherty Caitlin as Student Choir

Talya Grumberg as Student Choir

Rachel Moody as Student Choir

Jessica Muirhead as Student Choir

Bohdanna Novak as Student Choir

Gael O'Shaughnessy as Student Choir

Iwan Edwards as Choir Conductor

Shannon Cohen as Pirates of Penzance

Zosia Bornik as Pirates of Penzance

Michele Tredger as Pirates of Penzance

Erica Danya Goldblatt as Pirates of Penzance

Daniel Murphy as Pirates of Penzance

Chad Connell as Pirates of Penzance

Christopher Dyson as Pirates of Penzance

Eric Biunno as Pirates of Penzance

Andrea Shuster as Pirates of Penzance

Edward Lafferty as Pirates of Penzance

Sherry O'Connell as Pirates of Penzance

Nathalie Beaudoin as Pirates of Penzance

Emily Lamarche as Pirates of Penzance

Andrew Burr as Pirates of Penzance

Mark Hauser as Pirates of Penzance

Jeffrey Wetsch as Pirates of Penzance

Sacha Medine as Pirates of Penzance

Eli Udell as Pirates of Penzance

John Gilbert as Pirates of Penzance

Bombyx Du Murier as Pirates of Penzance

Marc Gourdeau as Client De La Tabagie

Eric Benton as Ski Mask Guy (uncredited)

Claudia Besso as Susan Bunwell (uncredited)

Josh Kimmel as Grieving Student (uncredited)

Camille Wainwright as Ellie Watson (uncredited)

Elizabeth Whitmere as Mrs. Burke (uncredited)