Actors in both NCIS and The X-Files
210 actors have appeared in both NCIS and The X-Files, across 726 episodes. The most-credited is Mitch Pileggi, U.S. Secretary of Defense Wynn Crawford in NCIS and Assistant Director Walter Skinner in The X-Files.
| Actor | In NCIS | In The X-Files | Eps | Eps |
|---|---|---|---|---|
| Mitch Pileggi | U.S. Secretary of Defense Wynn Crawford | Assistant Director Walter Skinner | 2 | 70 |
| Joe Spano | Tobias C. Fornell | Mike Millar | 56 | 2 |
| Alan Dale | Tom Morrow | Toothpick Man | 16 | 4 |
| Brian Thompson | Master Chief Vince Nutter | Bounty Hunter | 1 | 9 |
| Melinda McGraw | Diane Sterling | Melissa Scully | 6 | 4 |
| Mimi Rogers | CIA Officer Joanna Teague | Agent Diana Fowley | 3 | 6 |
| Susanna Thompson | Army Lt. Col. Hollis Mann | Michelle Generoo | 8 | 1 |
| John Finn | Marine Commandant Charles T. Ellison | Michael Kritschgau | 3 | 5 |
| Elayn J. Taylor | Odette Malone | Nurse #2 | 5 | 1 |
| Roger Cross | Lt. Cmdr. David Warfield | Field Agent, Officer Wentworth, Private Kittel | 1 | 4 |
| Adam Baldwin | Cdr. Rainer | Knowle Rohrer | 1 | 6 |
| Catherine Dent | Former NCIS Special Agent Whitney Sharp | June Gurwitch | 2 | 1 |
| Don S. Davis | MTAC Control Officer | Captain William Scully | 1 | 2 |
| Don Swayze | Logan Clay, Pete Walker | Terry Pruit | 2 | 1 |
| Doug Savant | Larry Clannon, Marine Brigadier General Daniel Kent | Augustus Goldman | 2 | 1 |
| Jack McGee | Det. Floyd, Richard "Rick" Jordan | Bob Damphouse | 2 | 1 |
| James Morrison | CIA Assistant Director Jonathan Overmeier, U.S. Senator John Phillips | Dr. Robert Wieder | 2 | 1 |
| Nick Chinlund | Detective Steve Rosetti | Donald Eddie Pfaster | 1 | 2 |
| Terry O'Quinn | Colonel Will Ryan | Lieutenant Brian Tillman, Shadow Man | 1 | 2 |
| William Devane | Nicolas Mason | General Mark A. Suveg | 1 | 2 |
Cast data from TVmaze, licensed CC BY-SA 4.0.