Jason Lee

Character: Shoeshine / Underdog (voice)

Peter Dinklage

Character: Dr. Simon Barsinister

Jim Belushi

Character: Dan Unger

Patrick Warburton

Character: Cad

Alex Neuberger

Character: Jack Unger

Taylor Momsen

Character: Molly

John Slattery

Character: Mayor

Amy Adams

Character: Polly Purebred (voice)

Brad Garrett

Character: Riff Raff (voice)

Samantha Bee

Character: Principal

Timothy Crowe

Character: Police Chief

Larry Vigus

Character: Security Guard

Mario Mariani

Character: Police Officer

Bates Wilder

Character: Cop

Alexander 'Alex' Garde

Character: Small Boy

Christopher Francis Byrnes

Character: Mailman (as Christopher Byrnes)

Joe Siriani

Character: News Stand Guy (as Joseph Siriani)

Sujoy De

Character: Office Worker #1

Michele Proude

Character: Office Worker #2

Albert M. Chan

Character: Geek Worker

Jon Pierce

Character: Hot Dog Vendor

Susie Castillo

Character: Diana Flores

Bob Jaffe

Character: Professor

Bruce-Robert Serafin

Character: City Worker (as Bruce Serafin)

Lonnie Farmer

Character: Passerby

Anthony Estrella

Character: Male School Teacher (as Tony Estrella)

Malik McMullen

Character: Bomb Squad Officer

Aaron Dorsey

Character: Little Boy

Walter Covell

Character: Old Man

Kate Lohman

Character: Housewife

Lewis D. Wheeler

Character: Geek with Glasses

Ellen Withrow

Character: Female Teacher

John M. Deluca

Character: Newscaster

Frank Ridley

Character: Police Sergeant

Grady Justice

Character: College Guy

Courtney O'Reagan

Character: College Girl

Rebekah Aramini

Character: Fox Collar Lady

Richney Fischer

Character: Baseball Dad

Joe Stapleton

Character: Cat Burglar Police #1

Armen Garo

Character: Cat Burglar Police #2

Daniel Kirby

Character: News Director

Stephen James Kidd

Character: Bomb Squad Member (as Steve Kidd)

Rena Maliszewski

Character: Mother

Diana Shneider

Character: Police Secretary

Barry Blair

Character: SWAT Captain

Bob Boehm

Character: Bomb Squad Officer #2 (as Robert Boehm)

Lincoln P. Sisson

Character: Bomb Squad Officer #3

Gabriel Field

Character: Lyle

Harry L. Thomas

Character: Police Artist

Amy Tanner

Character: Kissing Girl

Nicole Kopka

Character: Jogger in Park

Adam McCarthy

Character: Capitol City Security

Roy Souza

Character: Capitol City Cop

Tom Paolino

Character: Capitol City Cop

Scott Dittman

Character: Hot Dog Contestant

Ezra Buzzington

Character: Referee

Chris Andrew Ciulla

Character: Fireman (as Chris Ciulla)

Jay Leno

Character: Jay Leno

Phil Morris

Character: Supershep 1 (voice)

Michael Massee

Character: Supershep 2 (voice)

Cam Clarke

Character: Little Brown Dog / Supershep 3 (voice)

John DiMaggio

Character: Bulldog / Supershep 4 (voice)

Danny Mastrogiorgio

Character: Crazy Dog (voice)

Jess Harnell

Character: Astronaut (voice)

Joe Bucaro III

Character: Goon #1

Stuart F. Wilson

Character: Goon #2

John Franchi

Character: Observer (uncredited)

Susan Garfield

Character: Office Worker (uncredited)

Michael Tyler Henry

Character: Jack Unger (voice)