| Jennifer Garner | Sydney Bristow |
| Ron Rifkin | Arvin Sloane |
| Michael Vartan | CIA Agent Michael Vaughn |
| Carl Lumbly | Marcus Dixon |
| Kevin Weisman | Marshall Flinkman |
| Melissa George | Lauren Reed |
| Greg Grunberg | Agent Eric Weiss |
| David Anders | Mr. Sark |
| Lena Olin | Irina Derevko/Laura Bristow |
| Victor Garber | Jack Bristow |
| Past Cast | |
| Bradley Cooper | Will Tippin |
| Merrin Dungey | Francine "Francie" Calfo |