Ed Asner
Mr. Harris (voice) (as Ed Asner)

Angela Bassett
Miles' Mom (voice)

Lucas Black
Randy (voice)

Theodore Borders
Martin at Age 12 (voice)

LeVar Burton
Martin at Age 26 (voice) (as Levar Burton)

Jessica Garcia
Maria (voice)

Danny Glover
Train Conductor (voice)

Whoopi Goldberg
Mrs. Peck (voice)

Samuel L. Jackson
Turner (voice)

James Earl Jones
Daddy King (voice)

Ashley Judd
Mrs. Dale (voice)

Richard Kind
Mr. Willis (voice)

John Travolta
Kyle's Dad (voice)

Jaleel White
Martin at Age 15 (voice)

Susan Sarandon
Mrs. Clark (voice)

Oprah Winfrey
Coretta Scott King (voice)

Frank Welker
Bull Connor / Chihuahua (voice)

Yolanda King
Christine King (voice)

Dexter King
Martin - Age 34 (voice) (as Dexter Scott King)

Zachary Leigh
Kyle (voice)