- Don Adams
- Inspector Gadget
- Holly Berger
- Penny
- Frank Welker
- Brain / Dr. Claw / M.A.D Cat / The Lesser Wambini (segments "Magic Gadget" & "The Great Wambini's Seance") / News Reporter & Animals (segment "The Great Wambini's Seance") / M.A.D Agent (segment "The Capeman Cometh") (voice)
- Louis Nye
- The Great Wambini (segments "The Great Wambini's Seance" & "Magic Gadget")
- Andy Goldberg
- M.A.D Ninja (segment "The Capeman Cometh")
- Diz White
- Female Millionaire (segment "The Great Wambini's Seance")
- Ronald E. House
- Old Man (segment "The Great Wambini's Seance") / M.A.D Agent (segment "The Capeman Cometh") (voice)
- Maurice LaMarche
- Chief Quimby
- Townsend Coleman
- Cpl. Capeman (segment "The Capeman Cometh")
