Emile Hirsch
Christopher McCandless / Alexander Supertramp
Marcia Gay Harden
Billie McCandless
William Hurt
Walt McCandless
Jena Malone
Carine McCandless / Additional Narration (voice)
Catherine Keener
Jan Burres
Vince Vaughn
Wayne Westerberg
Kristen Stewart
Tracy Tatro
Hal Holbrook
Ronald "Ron" Franz
James J. O'Neill
Graduation Reader
Paul Knauls
Building Manager
Craig Mutsch
Wayne's Crew #1
Jim Beidler
Wayne's Crew #2
Terry Waldner
Hutterite #4
Steven Wiig
Lee's Ferry Ranger
Floyd Wall
Man In Phone Booth
Bryce Walters
Christopher McCandless (age 4)
Jim Davis
Immigration Officer
Cheryl Francis Harrington
Social Worker
Haley Ramm
Carine McCandless (age 11)
Everett 'Insane Wayne' Smith
Insane Cain
Leonard Knight
Leonard Knight
Matt Contreras
Book Shopper #1
Denise Sitton
Book Shopper #2
Sharon Olds
Additional Narration (voice)
Carine McCandless
Additional Narration (voice)
J. Nathan Simmons
Tourist (uncredited)
Parris Mosteller
Young Boy (voice) (uncredited)
Timothy Levine
Atlanta Braves fan (uncredited)
Haley Sweet
Bank Teller (uncredited)
Aaron Wayne Hill
Big Wheel Boy (uncredited)