 | Walter Brennan als D.J. Mulrooney / Knobby |
 | Matthew Garber als Rodney |
 | Karen Dotrice als Elizabeth |
 | Richard Deacon als Ralph Yarby |
 | Sean McClory als Horatio Quaxton |
 | Ed Wynn als Rufus |
 | Jerome Cowan als Dr. Ramsey |
 | Charles Lane als Dr. Scoggins |
 | Gil Lamb als Gas Attendant |
 | Maudie Prickett als Katie Barrett |
 | Cami Sebring als Violet |
 | Tom Lowell als Jasper |
 | Norman Grabowski als Male Nurse |
 | Ellen Corby als Etta Pettibone (uncredited) |
 | Byron Foulger als Hotel Desk Clerk (uncredited) |
| Robert Stevenson | Director |
| Edward Colman | Director of Photography |
| Carroll Clark | Art Direction |
| William H. Tuntke | Art Direction |
| Emile Kuri | Set Decoration |
| Hal Gausman | Set Decoration |
| Peter Ellenshaw | Matte Painter |
| Eustace Lycett | Special Effects |
| Robert A. Mattey | Special Effects |
| Robert O. Cook | Sound Supervisor |
| Dean Thomas | Sound Mixer |
| Bill Thomas | Costume Design |
| Chuck Keehne | Costumer |
| Neva Rames | Costumer |
| La Rue Matheron | Hairstylist |
| Pat McNalley | Makeup Artist |
| Evelyn Kennedy | Music Editor |
| Norman R. Palmer | Editor |
| Arthur J. Vitarelli | Second Unit Director |
| Joseph L. McEveety | Unit Manager |
| Paul Cameron | Assistant Director |
| Buddy Baker | Original Music Composer |
| Wayne Robinson | Orchestrator |
| Robert B. Sherman | Songs |
| Richard M. Sherman | Songs |
| Ellis Kadison | Screenplay |
| Upton Sinclair | Novel |
| James Algar | Co-Producer |
