| Name | Character | Episodes |
|---|---|---|
| Ed Asner | Sgt. Cosgrove (voice) | 24 |
| Paul Rugg | Freakazoid (voice) | 24 |
| David Warner | The Lobe (voice) | 9 |
| David Kaufman | Dexter Douglas (voice) | 9 |
| Jonathan Harris | Professor Jones (voice) | 6 |
| Ricardo Montalban | Armondo Guitierrez (voice) | 5 |
| Tress MacNeille | Debbie Douglas (voice) | 5 |
| Jeff Bennett | Cave Guy (voice) | 4 |
| Tress MacNeille | Cobra Queen (voice) | 4 |
| Googy Gress | Duncan Douglas (voice) | 4 |
| Frank Welker | Mr. Chubbikins (voice) | 3 |
| Craig Ferguson | Roddy MacStew (voice) | 3 |
| Maurice LaMarche | The Brain (voice) | 2 |
| Maurice LaMarche | Longhorn (voice) | 2 |
| Jess Harnell | Wakko (voice) | 2 |
| Ed Gilbert | Professor Heiny (voice) | 2 |
| Larry Cedar | Oblongata (voice) | 2 |
| Mark Hamill | 1 | |
| Frank Welker | 1 | |
| Frank Welker | Fred the Guard (voice) | 1 |
| Frank Welker | Dinosaur (voice) | 1 |
| Frank Welker | Gen. Toku (voice) | 1 |
| Frank Welker | Gulliver (voice) | 1 |
| Frank Welker | Big Snake (voice) | 1 |
| Jim Cummings | Janos (voice) | 1 |
| Jim Cummings | Semiconductor (voice) | 1 |
| Jim Cummings | The Wolfman (voice) | 1 |
| Jim Cummings | Ape Monster (voice) | 1 |
| Tim Curry | Dr. Mystico (voice) | 1 |
| John Rhys-Davies | Professor Beasthead (voice) | 1 |
| Jeff Bennett | Candle Jack (voice) | 1 |
| Jeff Bennett | Manager (voice) | 1 |
| Jeff Bennett | Medulla (voice) | 1 |
| Jeff Bennett | The Huntsman (voice) | 1 |
| Jeff Bennett | Attendant (voice) | 1 |
| Jeff Bennett | Bearded Archeologist (voice) | 1 |
| Jeff Bennett | Jeepers (voice) | 1 |
| Jeff Bennett | Mike (voice) | 1 |
| Jeff Bennett | Keir (voice) | 1 |
| Dave Coulier | Teenage Boy (voice) | 1 |
| Elisabeth Moss | Kathy (voice) | 1 |
| Brian George | Doc (voice) | 1 |
| Brian George | Warden Riba (voice) | 1 |
| Andrea Martin | Female Neighbor (voice) | 1 |
| Tress MacNeille | Secretary (voice) | 1 |
| Tress MacNeille | Anchorwoman (voice) | 1 |
| Tress MacNeille | Mary Beth (voice) | 1 |
| Tress MacNeille | Speaker Voice (voice) | 1 |
| Tress MacNeille | Babeheart (voice) | 1 |
| Rob Paulsen | Francois (voice) | 1 |
| Rob Paulsen | Yakko (voice) | 1 |
| Rob Paulsen | Mohammed-Abdul (voice) | 1 |
| Rob Paulsen | Pinky (voice) | 1 |
| Maurice LaMarche | 1 | |
| Maurice LaMarche | Dan (voice) | 1 |
| Clive Revill | Hermil Sioro (voice) | 1 |
| Cree Summer | Jill (voice) | 1 |
| Kenneth Mars | Dr. Hunterhanker (voice) | 1 |
| Richard Moll | Vorn the Unspeakable (voice) | 1 |
| Scott Menville | Toby Danger (voice) | 1 |
| Jess Harnell | Singer (voice) | 1 |
| Carl Ballantine | 1 | |
| Leonard Maltin | Himself (voice) | 1 |
| Craig Ferguson | Roddy Mac Stew (voice) | 1 |
| Stephen Furst | 1 | |
| Bebe Neuwirth | Deadpan (voice) | 1 |
| Dorian Harewood | Deep Voiced Singer (voice) | 1 |
| Dorian Harewood | Singer #4 (voice) | 1 |
| Dorian Harewood | Singer #1 (voice) | 1 |
| Larry Cedar | Anton (voice) | 1 |
| Larry Cedar | Chip (voice) | 1 |
| Corey Burton | Invisibo (voice) | 1 |
| Neil Ross | Board Member (voice) | 1 |
| Don Messick | Dr. Vernon Danger | 1 |
| Mary Scheer | Sandra Danger (voice) | 1 |
| Mitch Schauer | Lonnie Tallbutt (voice) | 1 |
| Mitch Schauer | The Door Keeper (voice) | 1 |
| Granville Van Dusen | Dash O'Pepper (voice) | 1 |
| Randy Crenshaw | Waiter #1 (voice) | 1 |
| Randy Crenshaw | Attendant #1 (voice) | 1 |
| Jack Valenti | Himself (voice) | 1 |
| Stan Freberg | 1 | |
| Mari Devon | Tammy (voice) | 1 |