| David Duchovny | Fox Mulder |
| Gillian Anderson | Dana Scully |
| Mitch Pileggi | Walter Skinner |
| William B. Davis | Smoking Man |
| Charles Cioffi | Section Chief Scott Blevins |
| Sheila Larken | Margaret Scully |
| Pat Skipper | Bill Scully Jr. |
| Megan Leitch | Samantha Mulder |
| Tom Braidwood | Melvin Frohike |
| Dean Haglund | Richard 'Ringo' Langly |
| Bruce Harwood | John Fitzgerald Byers |
| John Finn | Michael Kritschgau |
| Robert Wright | Dr. Zuckerman |
| Ken Camroux-Taylor | Senior Agent
(as Ken Camroux) |
| Don S. Williams | Elder |
| Arnie Walters | Father McCue |
| Brent Sheppard | Doctor |
| Catherine Barroll | Secretary
(uncredited) |
| Erin Fitzgerald | Waitress
(uncredited) |
| Tom Harkin | Self
(archive footage) (uncredited) |
| Ted Kennedy | Self
(archive footage) (uncredited) |
| Willy Ross | Quiet Willy
(uncredited) |