All 147 actors in both Smallville and The X-Files
147 actors have appeared in both Smallville and The X-Files, across 435 episodes. The most-credited is William B. Davis, Mayor William 'Billy' Tate in Smallville and Cigarette-Smoking Man in The X-Files.
| Actor | In Smallville | In The X-Files | Eps | Eps |
|---|---|---|---|---|
| William B. Davis | Mayor William 'Billy' Tate | Cigarette-Smoking Man | 2 | 44 |
| Bruce Harwood | Ben Powell | John Fitzgerald Byers | 1 | 38 |
| Mitchell Kosterman | Sheriff Ethan Miller | Detective Horton, Fornier, Sheriff | 14 | 4 |
| Alessandro Juliani | Dr. Emil Hamilton | Joseph Cutler | 14 | 1 |
| Sarah Jane Redmond | Nell Potter | Karin Matthews, Young Mother | 11 | 2 |
| Mike Dopud | Security Guard George | Mr. Y's Henchman | 10 | 1 |
| Hiro Kanagawa | Principal H. James Kwan | Dr. Yonechi, Garner, Peter Tanaka | 5 | 3 |
| Malcolm Stewart | Dr. Otis Ford, Dr. Sinclair, Jim Melville | Dr. Sacks, Agent Bonnecaze, Commander Carver | 3 | 5 |
| Robert Wisden | Gabe Sullivan | Robert Patrick Modell aka Pusher | 6 | 2 |
| Sharon Taylor | Faora | Diana Eggers | 7 | 1 |
| Tom O'Brien | Roger Nixon | Corporal Frish | 5 | 2 |
| Fred Henderson | Dr. Langston | Agent Rich, Agent Thomas | 4 | 2 |
| Jerry Wasserman | Dr. Yaeger Scanlan | Dr. John Grago, Dr. Plith | 4 | 2 |
| Michael McKean | Perry White | Morris Fletcher | 2 | 4 |
| Stephen Lobo | Randall Brady | Dark-Suited Man #1 | 5 | 1 |
| William MacDonald | Walt Masterson | Agent Dan Kazanjian, Buddy Riggs, Dr. Oppenheim | 1 | 5 |
| Gillian Barber | Marianne Taylor | Penny Northern, Agent Jane Spiller, Beth Kane | 1 | 4 |
| Joe Morton | Dr. Steven Hamilton | Martin Wells | 4 | 1 |
| Colin Lawrence | Agent Stocker, Captain Nichols, Doctor | Cop #1 | 3 | 1 |
| Rob LaBelle | Dr. Fredrick Walden | Brad Wilczek | 3 | 1 |
| Callum Keith Rennie | Tyler McKnight | Groundskeeper, Tommy Philips | 1 | 2 |
| Chad E. Donella | Greg Arkin / Bug Boy | Rob Roberts | 2 | 1 |
| Donnelly Rhodes | Milash | General Francis, Jim Parker | 1 | 2 |
| Gordon Tootoosis | Prof. Joseph Willowbrook | Shaman | 2 | 1 |
| Lorena Gale | Dr. Claire Foster | Attorney, Ellen Bledsoe, Nurse Wilkins | 3 | 3 |
| Michael David Simms | Dr. Neil Moore | Senior FBI Agent | 1 | 5 |
| Teryl Rothery | Board Member #2, Real Estate Agent | Nurse Michelle Charters | 2 | 1 |
| Christine Willes | Granny Goodness | Agent Karen Kossef, Sister Mary | 4 | 4 |
| Chris Shields | Courier, EMT #1, Reporter | Detective Dross | 4 | 1 |
| David Lewis | Dr. Marcus, Macy / Jeweler | Vosberg, Young Agent, Young Officer | 2 | 3 |
| Don Thompson | Jack Cole | Henry Willig, Holtzman, Lieutenant Colonel Victor Stans | 2 | 3 |
| Jill Teed | Detective Maggie Sawyer | Glenna | 4 | 1 |
| Joe Maffei | Newspaper Stand Worker, Janitor | Guard #1, Motel Manager | 3 | 2 |
| Rob Freeman | Coach Wayne Quigley | Detective Rempulski, Marshall Sim | 3 | 2 |
| Scott Bellis | Vice Principal Martin Gibbons, Wendell Kerns | Max Fenig | 2 | 3 |
| Julian D. Christopher | Dr. MacIntyre | Dr. Oscar Griffiths | 6 | 1 |
| Alan C. Peterson | Senator Ed Burke | Mr. Y | 2 | 2 |
| Gerard Plunkett | Dr. Donovan Jamison | Dr. Calderon | 2 | 2 |
| Ian Tracey | Lincoln Cole | Sergeant Leonard 'Rappo' Trimble | 1 | 1 |
| John DeSantis | Male Zoner, Solomon Grundy, The Traveler | Band-Aid Nose Man | 3 | 1 |
| John Pyper-Ferguson | Dr. William McBride | Det. John Kresge, Paul | 1 | 3 |
| Katharine Isabelle | Sara Conroy | Lisa Baiocchi | 1 | 1 |
| Kevin McNulty | Mr. Summers | Agent Fuller, Dr. Christopher Davey | 1 | 3 |
| Kevin Zegers | Seth Nelson | Kevin Kryder | 1 | 1 |
| Krista Allen | Desiree Atkins | Jade Blue Afterglow / Maitreya | 1 | 1 |
| Ryan Robbins | Louis Leery Jr. | Murphy | 1 | 1 |
| Tim Henry | Private Investigator Mason | Federal Marshall, Plain-Clothed Man | 2 | 2 |
| Eric Breker | Roy Rothman | Dark-Suited Man #1, Admitting Officer, SP Agent Brem | 1 | 4 |
| George Murdock | Old Harry Bollston | Elder #3 | 1 | 4 |
| Steve Bacic | Garage Worker, Vordigan / Dark Archer | Agent Collins, Officer #2, S.W.A.T. Commander | 2 | 3 |
| Aaron Douglas | Deputy Michael Vertigo, Pierce | Lindquist | 2 | 1 |
| Blu Mankuma | Franklin W. Stern | Claude Peterson, Det. Pennock | 1 | 2 |
| Gabrielle Rose | Mrs. Arkin | Dr. Zenzola, Mrs. Anita Budahas | 1 | 2 |
| Matthew Walker | Dr. Hudson | Arlinsky, Dr. Ronald Surnow | 1 | 2 |
| Paul Jarrett | Scientist | James Earl Ray, Upshaw | 1 | 2 |
| Dean Redman | Lab Guard, Police Officer, Policeman | Police Officer | 3 | 1 |
| Kwesi Ameyaw | Darius | Judge | 3 | 1 |
| Lori Ann Triolo | Lt. Trotter | Diane | 3 | 1 |
| Veena Sood | Schoolteacher | Dr. Louise Colquitt, Mrs. Saunders | 2 | 2 |
| Chilton Crane | Guidance Counselor | Sharon Graffia, Margaret Hohman, Mother at Bus Station | 1 | 4 |
| Steve Makaj | Coach Calloway, Contractor | Scott Ostelhoff, Frank Kiveat, Patrolman | 2 | 4 |
| Ben Cotton | Paul Hendrix | Mr. Paulsen | 1 | 2 |
| Dalias Blake | Security Guard | Cop #2 | 1 | 1 |
| Eileen Pedde | Jennifer Small | Angie, Mrs. Skur | 2 | 2 |
| Glynis Davies | Mrs. Palmer | Ellen, Monica Landis, Nelson | 1 | 3 |
| Jonathan Lloyd Walker | Paul Brenner | Chuck Lukerman | 2 | 1 |
| Judith Maxie | Dr. Albright | Barbara Taylor | 2 | 1 |
| Mark Acheson | Magistrate Wilkins | Ted Bertram, Trucker | 2 | 2 |
| Merrilyn Gann | Ruth Cavanaugh | Mrs. Asekoff, Prosecutor | 1 | 2 |
| Michael Puttonen | Dr. Caselli | Conductor, Dr. Pilsson, Martin Allpert | 1 | 4 |
| Sebastian Spence | Ted Kord | Deputy Barney Paster | 1 | 1 |
| Sheila Moore | Rose Randall | Mrs. Dawson, Verla McLennen | 1 | 2 |
| Viv Leacock | Agent Simon, Co-Pilot | Price | 2 | 1 |
| Don MacKay | Las Vegas Minister | Charlie, Judge, Oates | 1 | 4 |
| Arnie Walters | Reverend | Father McCue | 1 | 3 |
| Brad Loree | Bartender, Surgeon | Fireman, Security Guard | 2 | 2 |
| J.B. Bivens | Museum Security Guard | Field Agent, Sharpshooter, Truck Driver | 1 | 3 |
| Linden Banks | Jonah Doyle, Scientist | Joseph Patnik, Reverend Sistrunk | 2 | 2 |
| Brent Sheppard | Detective Berg | Doctor, Prosecutor | 1 | 2 |
| Dean McKenzie | Lex's Campaign Manager | Army Tech | 2 | 1 |
| Gardiner Millar | FBI Agent | Eugene Baiocchi, Man in Suit | 1 | 2 |
| Michael Rogers | Agent Black | Crewman #1, Lt. Griffin | 1 | 2 |
| Tom Butler | Lawrence Grady | Benjamin Drake, CIA Agent Ambrose Chapel | 1 | 2 |
| Zak Santiago | Deputy Morales | Mr. Green | 1 | 2 |
| Alvin Sanders | Dale Ross, Dr. Klein | Bus Driver, Deputy Wright | 2 | 2 |
| Brent Stait | Kent Nelson / Dr. Fate | Timothy Mayhew, Corp. Taylor | 1 | 3 |
| Candus Churchill | Nurse | Shirley | 1 | 1 |
| Colin Cunningham | Nicky Taylor | Dr. Henry Stroman, Escalante, Lt. Terry Wilmer | 1 | 3 |
| Daryl Shuttleworth | Vice Principal Martin Gibbons | Daryl Landry | 1 | 1 |
| David Lovgren | Derek Fox | Kurt Crawford | 1 | 1 |
| Douglas Arthurs | Snake | Skin-Head Man | 1 | 1 |
| Ken Kirzinger | Scientist | Richter | 1 | 1 |
| Kenneth Welsh | Drunk Santa | Simon Gates / Millenium Man | 1 | 1 |
| Mark Gibbon | Mr. Raines, Orderly, SWAT Commander | Guard | 3 | 1 |
| Michael Kopsa | Dean Winters | Rick Culver | 1 | 1 |
| Tony Todd | Earl Jenkins | Augustus Cole | 1 | 1 |
| Ty Olsson | Officer Talbert | Younger Orderly | 1 | 1 |
| William S. Taylor | Mr. Jacobson | General Leitch | 1 | 1 |
| Andrew Johnston | Schoolteacher | Agent Barry Weiss, Lt. Col. Robert Budahas, Medical Examiner | 1 | 4 |
| Brenda Crichlow | Guidance Councilor, News Reporter | Reporter | 2 | 1 |
| French Tickner | Buster Breyfogle, Simon Westcott | Preacher | 2 | 1 |
| Lynda Boyd | Mrs. Baker | Bar Patron, Elizabeth | 1 | 2 |
| Nathaniel DeVeaux | Commander | Detective Barron | 2 | 1 |
| Alfred E. Humphreys | Jim Gage | Dr. Mark Pomerantz, Michael Asekoff, Mission Controller #2 | 1 | 3 |
| P. Lynn Johnson | Mrs. Summers | Deborah Brown, Dr. Sheila Braun, Health Department Doctor | 1 | 3 |
| Adrian G. Griffiths | Blackmailer | Sherman Peacock | 1 | 1 |
| Anthony Harrison | Head Astronomer | 4th Man, Agent Riggins | 1 | 2 |
| Benita Ha | Dr. Asuka | Tour Guide | 1 | 1 |
| D. Neil Mark | Lt. Ray McNulty | Deputy Scott Kerber, SWAT Team Officer | 1 | 2 |
| Ellie Harvie | Marge Manners | OPO Staffer | 1 | 1 |
| Frank C. Turner | Eddie Cole, Joe | Dr. Collins, Dr. Del Hakkie | 2 | 2 |
| Fulvio Cecere | Swim Coach Rick Varley | Aide, Priest | 1 | 2 |
| Ian Robison | Pilot | Detective Smith, Ranger | 1 | 2 |
| Kate Robbins | Mrs. Allen | Lisa's Aunt, Mrs. Oswald | 1 | 2 |
| Randy Lee | Security Guard #2 | Paramedic | 1 | 1 |
| Terence Kelly | Doctor | George Usher | 1 | 1 |
| Tom Heaton | Dexter 'Dex' McCallum | Groundskeeper | 1 | 1 |
| Deryl Hayes | Detective | Agent Morris, Army Doctor, Webster | 1 | 3 |
| Andrew Airlie | Mr. Woodruff | Attorney, Rob | 1 | 2 |
| Dean Wray | Hiram Kent | Rich Turner, Tow Truck Driver | 1 | 2 |
| Michael St. John Smith | Dr. Thomas Burton, General | Major General Fryatt | 2 | 1 |
| Patrick Keating | Dr. Heller | Beggar, Donald Gelman | 1 | 2 |
| Roger Haskett | Ted Grant / Wildcat | Coroner, Deputy Tyson | 1 | 2 |
| Alison Araya | Nurse | Nurse Vickie Easton | 1 | 1 |
| Cam Cronin | Dr. Glenn | Paramedic | 1 | 1 |
| Eric Keenleyside | Mike | Lance Kernof | 1 | 1 |
| Paul McGillion | LexCorp Employee | Fred Neiman | 1 | 1 |
| Peter Flemming | Brady | Officer #1 | 1 | 1 |
| Todd Mann | Twin #2 | FBI Agent #2 | 1 | 1 |
| Tom Pickett | Principal Terrence Reynolds | Cop | 1 | 1 |
| Danny Wattley | Deputy | First Officer | 1 | 1 |
| Jase Anthony Griffith | Belle Reve Guard | Paramedic #1 | 1 | 1 |
| Rob Morton | Second Foreman | Kramer | 1 | 1 |
| Scott Swanson | Doctor | First Officer | 1 | 1 |
| Michael Ryan | Psychiatrist | Agent Cameron Hill, Overcoat Man | 1 | 2 |
| Allan Franz | Wayne Quigley | Dr. Ben Keyser | 1 | 1 |
| Catherine Lough Haggquist | Mary | Dr. Richmond | 1 | 1 |
| Donald Fong | Factory Worker | Vase Man | 1 | 1 |
| James R. Baylis | Priest | Homeless #1 | 1 | 1 |
| Jayme Knox | Ryan's Aunt | Mom | 1 | 1 |
| R. Nelson Brown | Dr. Toby | Ansel Bray | 1 | 1 |
| Ralph Alderman | Hank Pond | Manager | 1 | 1 |
| Bill Finck | Jules Casey | Sandwich Man | 1 | 1 |
| Kurt Evans | EMT | Sports Store Employee | 1 | 1 |
| Jeremy Jones | Henry's Father | Sergeant | 1 | 1 |
| Mina E. Mina | Egyptologist | Dr. Hand | 1 | 1 |
| Shelly Adam | Recepionist | Teena Mulder | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.