Casey Kasem as (voices)

E. G. Daily as Buttercup (Voice)

Mae Whitman as Little Suzy (Voice)

Tara Strong as Bubbles (Voice)

Jeff Bennett as Jhonny Bravo (Voice)

Cathy Cavadini as Blossom (Voice)

Christine Cavanaugh as Dexter (Voice)

Charlie Adler as I.R. Baboon (Voice) / Cow (Voice) / Chicken (Voice) / Red Guy (Voice)

Richard Steven Horvitz as Billy (Voice)

Grey DeLisle as Mandy (Voice)

Brenda Vaccaro as Bunny Bravo (Voice)

Greg Eagles as The Grim Reaper (Voice)

Tom Kane as Professor Utonium (Voice)

Tom Kenny as The Mayor (Voice)

Charlie Adler as I.R. Baboon

Michael Dorn as I.M. Weasel (Voice)

Marty Grabstein as Courage (Voice)

Thea White as Muriel Bagge

Thea White as Muriel Bagge (Voice)

Allison Moore as Dee Dee (voice)

Frank Welker as (voices)

Mindy Cohn as (voice)

Jim Cummings as (voice)

Mark Hamill as (voices)

William Hanna as (voice)

Joseph Barbera as (voice)

Ted Turner as (archive footage)

Don Messick as (archive footage)