Sean Penn

Director

Emile Hirsch

Christopher McCandless / Alexander Supertramp

Marcia Gay Harden

Billie McCandless

William Hurt

Walt McCandless

Jena Malone

Carine McCandless / Additional Narration (voice)

Brian H. Dierker

Rainey

Catherine Keener

Jan Burres

Vince Vaughn

Wayne Westerberg

Kristen Stewart

Tracy Tatro

Hal Holbrook

Ronald "Ron" Franz

Thure Lindhardt

Mads

Signe Egholm Olsen

Sonja

Zach Galifianakis

Kevin

Steven Wiig

Lee's Ferry Ranger

Cheryl Francis Harrington

Social Worker

R. D. Call

Bull

Haley Ramm

Carine McCandless (age 11)

Merritt Wever

Lori

John Jabaley

Announcer

Leonard Knight

Leonard Knight

J. Nathan Simmons

Tourist (uncredited)

Haley Sweet

Bank Teller (uncredited)

Aaron Wayne Hill

Big Wheel Boy (uncredited)

Jim Gallien

Jim Gallien

James J. O'Neill

Graduation Reader

Malinda McCollum

Waitress

Paul Knauls

Building Manager

Craig Mutsch

Wayne's Crew #1

Jim Beidler

Wayne's Crew #2

John Decker

Hutterite #1

John Hofer

Hutterite #2

Jerry Hofer

Hutterite #3

Terry Waldner

Hutterite #4

Robin Mathews

Gail Borah

Candice Campos

Bar Girl

Floyd Wall

Man In Phone Booth

Bryce Walters

Christopher McCandless (age 4)

Jim Davis

Immigration Officer

Everett 'Insane Wayne' Smith

Insane Cain

Matt Contreras

Book Shopper #1

Denise Sitton

Book Shopper #2

Sharon Olds

Additional Narration (voice)

Carine McCandless

Additional Narration (voice)

Parris Mosteller

Young Boy (voice) (uncredited)

Timothy Levine

Atlanta Braves fan (uncredited)

Bart the Bear 2

Bear