"I learn that Chris McIntyre served in Vietnam and that "21 and a Wakeup," set in an Army hospital in the waning days of the war, is based on events that he experienced and heard about." - Roger Ebert
| Actor | Role |
|---|---|
 Amy AckerCaitlin Murphy | Caitlin Murphy |
 Danica McKellarJenny Valentine | Jenny Valentine |
 Faye DunawayMajor Rose Thorn | Major Rose Thorn |
 Cat LySong Li | Song Li |
| TTodd CahoonChris Cameron | Chris Cameron |
 Kristyn GreenSkylar Paige | Skylar Paige |
 Kieu ChinhMamason | Mamason |
 JC ChasezDr. Tom Drury | Dr. Tom Drury |
 Lê Y LanVietnamese Villager | Vietnamese Villager |
 Kenneth Chang24th Evac Staff and Patients | 24th Evac Staff and Patients |
 Wes StudiGeneral Gleason | General Gleason |
 Tim ThomersonNot listed | Not listed |
 Tom SizemoreNot listed | Not listed |
 Mạnh DungVietnamese Villager | Vietnamese Villager |
 Mạnh CườngVietnamese Villager | Vietnamese Villager |
 Nguyễn Hữu ThànhVietnamese Villager | Vietnamese Villager |