| Name | Character | Episodes |
|---|---|---|
| Ralph Bellamy | Dr. Theodore Bassett | 62 |
| Ralph Bellamy | Dr. L. Richard Starke | 62 |
| Jack Ging | Dr. Paul Graham | 62 |
| Wendell Corey | 32 | |
| Martin Balsam | 1 | |
| Elinor Donahue | 1 | |
| David Janssen | Hal Kincaid | 1 |
| Fay Wray | 1 | |
| Aneta Corsaut | 1 | |
| Katy Jurado | 1 | |
| Jean Stapleton | 1 | |
| Murray Hamilton | 1 | |
| Bill Mumy | 1 | |
| Barbara Rush | Linda Kincaid | 1 |
| Paul Newlan | 1 | |
| Alexander Scourby | Garrett Nolan | 1 |
| Grace Lee Whitney | Dawn | 1 |
| Fabian | 1 | |
| Richard Anderson | 1 | |
| Ed Asner | 1 | |
| Tuesday Weld | Denise Dunlear | 1 |
| Red Buttons | 1 | |
| Tom Lowell | Stan Jordan | 1 |
| Frank Overton | Pete Harvey | 1 |
| Davey Davison | 1 | |
| Susan Gordon | Jenny Kincaid | 1 |
| Philip Ober | 1 | |
| John Goddard | Doug | 1 |
| Mimi Dillard | Hilda | 1 |
| Madame Spivy | Jocetta | 1 |