| Cast list | | Emile Hirsch | as | Christopher McCandless | | Vince Vaughn | as | Wayne Westerberg | | Kristen Stewart | as | Tracy | | Catherine Keener | as | Jan Burres | | William Hurt | as | Walt McCandless | | Marcia Gay Harden | as | Billie McCandless | | Zach Galifianakis | as | Kevin | | Haley Ramm | as | Young Carine | | Thure Lindhardt | as | Thomas | | Signe Egholm Olsen | as | Thomas' girlfriend | | Susan Spencer | as | Parent | | J. Nathan Simmons | as | Tourist | | Bryce Walters | as | Chris McCandless at Age 4 | | Cheryl Francis Harrington | as | Social Worker | | Kyle Kwon | as | Ted Turner | | Robin Mathews | as | Gail Borah | | John Jabaley | as | Announcer | | Steven Wiig | as | Ranger Steve Koehler | | Haley Sweet | as | Bank Teller | | Joe Dustin | as | The Beast | | Kathleen Mattice | as | College student | | Dan Burch | as | Passerby |
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