| Name | Character | Episodes |
|---|---|---|
| Rupert Friend | Ernest Donovan | 17 |
| Jack Reynor | Jack Parsons | 17 |
| Rade Šerbedžija | Prof. Filip Mešulam | 17 |
| Michael Gaston | Virgil Byrne | 17 |
| Greg Wise | Alfred Miller | 17 |
| Peter Mark Kendall | Richard Onstead | 17 |
| Zack Pearlman | Samson Hunt | 17 |
| Amara Zaragoza | Joan | 17 |
| Bella Heathcote | Susan Parsons | 10 |
| Karl Makinen | General Braxton | 10 |
| Bradley James | Forensic Detective | 1 |
| Jake Lockett | Billy | 1 |