Emile Hirsch

as Christopher McCandless / Alexander Supertramp

Marcia Gay Harden

as Billie McCandless

William Hurt

as Walt McCandless

Jena Malone

as Carine McCandless / Additional Narration (voice)

Brian H. Dierker

as Rainey

Catherine Keener

as Jan Burres

Vince Vaughn

as Wayne Westerberg

Kristen Stewart

as Tracy Tatro