| Sirens focused on the work and lives of three rookie female Pittsburgh Police officers. Officer Sarah Berkezchuk is dealing with her failing marriage, Officer Lynn Stanton is a single mom, and second-generation cop Officer Molly Whelan has a bad attitude which starts to interfere with her job. Each rookie officer worked under a veteran cop, and each grows and becomes more focused as a result. |
| Name | Character | Episodes |
|---|---|---|
| Liza Snyder | Molly Whelan | 35 |
| Tim Thomerson | James "Buddy" Zunder | 35 |
| A.J. Johnson | Lynn Stanton | 35 |
| Christopher Judge | Richard Stiles | 22 |
| Jayne Heitmeyer | Jessie Jaworski | 22 |
| Ellen David | Amy Shapiro | 22 |
| J. H. Wyman | Lyle Soinger | 22 |
| John Terlesky | Dan Kelly | 13 |
| Deirdre O'Connell | Heidi Schiller | 13 |
| Jayne Brook | Sarah Berkezchuk | 13 |
| John Speredakos | Cary Berkezchuk | 13 |
| Anne-Marie Johnson | Christine | 1 |
| Jane Wheeler | Sheila | 1 |
| Jenny Wright | Reporter #2 | 1 |
| Wil Wheaton | Wayne McGarrick | 1 |
| Martha Hackett | 1 | |
| Bobby Hosea | 1 | |
| Bob Hiltermann | Jacob | 1 |