| Name | Character | Episodes |
|---|---|---|
| Shaun Johnston | 14 | |
| Sarah Lind | 13 | |
| Chad Krowchuk | 13 | |
| Chad Krowchuk | Oliver Cates | 13 |
| Jane Sowerby | 13 | |
| Barbara Mamabolo | 13 | |
| Sarah Lind | Dee Sampson | 6 |
| Peter Outerbridge | Dr. Milton Bradshaw | 3 |
| Katharine Isabelle | Annie Sullivan | 1 |
| Elliott Gould | Albert Einstein | 1 |
| Henry Czerny | Ludwig van Beethoven | 1 |
| Brian George | St. Nicholas | 1 |
| Emily Perkins | Mary Shelley | 1 |
| Tom Cavanagh | Lewis Carroll (as Thomas Cavanagh) | 1 |
| Matt Frewer | Frederick Banting | 1 |
| Eric Johnson | 1 | |
| Len Cariou | Alexander Graham Bell | 1 |
| Nick Mancuso | 1 | |
| Shaun Johnston | Roy Cates | 1 |
| Karen LeBlanc | Gina Lester | 1 |
| Michael Sarrazin | Edgar Allan Poe | 1 |
| Nigel Bennett | 1 | |
| Ellie Harvie | Cleopatra | 1 |
| Adam J. Harrington | Sandy Mear (as Adam Harrington) | 1 |
| Simon MacCorkindale | Oscar Wilde | 1 |
| Saul Rubinek | Napoleon Bonaparte | 1 |
| Yani Gellman | 1 | |
| Judy Norton | Ray Cates’ Girlfriend | 1 |
| Sandra Caldwell | Harriet Tubman | 1 |
| Heath Lamberts | P.T. Barnum | 1 |