All 126 actors in both 3rd Rock from the Sun and ER
126 actors have appeared in both 3rd Rock from the Sun and ER, across 470 episodes. The most-credited is John Aylward, Chancellor, Registrar in 3rd Rock from the Sun and Dr. Donald Anspaugh in ER.
| Actor | In 3rd Rock from the Sun | In ER | Eps | Eps |
|---|---|---|---|---|
| John Aylward | Chancellor, Registrar | Dr. Donald Anspaugh | 2 | 74 |
| David DeLuise | Bug Pollone | Brad Anderson | 44 | 1 |
| Chad Einbinder | Rico, Police Officer | Gordan | 12 | 1 |
| David Brisbin | Professor Brandon | Dr. Alexander Babcock | 1 | 19 |
| Shay Astar | August Leffler | Amy Thompson | 7 | 1 |
| Marianne Muellerleile | Lucy | Mrs. Jarnowski | 6 | 1 |
| J.P. Manoux | Clerk | Dr. Dustin Crenshaw, Mime | 1 | 24 |
| Justin Urich | Romano | Corky | 4 | 1 |
| John Mahoney | Dr. Leonard Hanlin | Bennett Cray | 1 | 1 |
| Michael McShane | Phil | Hugo | 1 | 1 |
| Miguel Ferrer | Jack | Mr. Parker | 1 | 1 |
| Cathrine Grace | Veronica | Mrs. Harrison, Ratkovich | 1 | 2 |
| Jennifer Rhodes | Mrs. Sumner | Mrs. Henry | 4 | 1 |
| Dennis Cockrum | Colonel Pinkham | Little League Player's Father | 1 | 1 |
| Diane Delano | Lorraine | Stella Willis, Delores | 1 | 5 |
| Eugene Elman | Stan | Jerry | 1 | 1 |
| Jim Jansen | Mr. Gindek | Neonatologist | 1 | 1 |
| Katherine LaNasa | Kate | Janet Wilco | 1 | 1 |
| Kathleen Garrett | Celia | Mrs. Meeker | 1 | 1 |
| Michael Dempsey | Security Guard | Mr. Beckwith | 1 | 1 |
| Patrick Kerr | Irving | George Deakins | 2 | 2 |
| Richard Fancy | Judge DeBelko | Mr. Thomas | 2 | 1 |
| Robert Clendenin | Man #1 | Anesthesiologist | 1 | 1 |
| Suanne Spoke | Bibi | Mrs. Robbins, OB Receptionist | 1 | 2 |
| Tim Bagley | Frank | Archie Papion | 1 | 1 |
| Alex Alexander | Tiffany | Betty, Carol Weddington | 1 | 2 |
| Bill Chott | Cable Guy, Fred | Glen Ashman | 2 | 1 |
| Bodhi Elfman | Clerk, Orderly | Nicky | 2 | 1 |
| Jack Carter | Uncle Abe | Kipke, Mickey Goldstein | 1 | 2 |
| Paul Hansen Kim | Kwan | Tech | 1 | 2 |
| Tim Haldeman | Mr. Kraft | Dr. Robert Wilson | 2 | 1 |
| Dee Freeman | Waitress, DMV Clerk | Dr. Lutz | 3 | 2 |
| Andrea Hutchman | Christie | Cousin Kelly | 1 | 1 |
| Barbara Lee Bragg | Karen | Giselle | 1 | 1 |
| Gloria LeRoy | Dolores | Beth Lang | 1 | 1 |
| Jeff Doucette | Chet | Larkowski | 3 | 1 |
| Jim O'Heir | Walt | McKenna | 1 | 1 |
| Ron Fassler | Auctioneer | Mr. Rosen | 1 | 1 |
| Sally Ann Brooks | Verna | Allison | 1 | 1 |
| Stephanie Erb | Ellen | Mrs. Kinney | 1 | 1 |
| Emile Hirsch | Punk | Chad Kottmeier | 1 | 2 |
| Lawrence Mandley | Carlos | Jackson, Maintenance Man | 1 | 2 |
| Aaron Paul | Student | Doug | 1 | 1 |
| Bob Bancroft | Father Matthew | Albert | 1 | 1 |
| Darlene Kardon | Old Woman | Elderly Woman | 1 | 1 |
| David A. Kimball | Vice President | tbd | 1 | 1 |
| Franc Ross | Man #2 | Naughton | 1 | 1 |
| Fred Pinkard | Louis | Mr. Stubey | 1 | 1 |
| Hubert Hodgin | Clerk #1 | Sal | 1 | 1 |
| Jerry Hauck | Frank | Umpire | 1 | 1 |
| Jonathan Palmer | Guest #1, Herve | Dr. Blevins | 2 | 1 |
| Lisa K. Wyatt | Hannah | Transpo Tech | 1 | 1 |
| Madison Mason | Mr. Jack Wallencott | Clive King | 1 | 1 |
| Miles Marsico | Freddy | David Bradley | 1 | 1 |
| Nancy Lenehan | Mrs. St. Clair | Edie Harvell | 1 | 1 |
| Raye Birk | Jeweler | Mr. Hartley | 1 | 1 |
| Rick Cramer | Stenstrom | McCormick, Officer O'Bannon | 1 | 2 |
| Robert Knott | Ellis | Donny | 1 | 1 |
| Trisha Simmons | T.V. Reporter #1 | Maureen | 1 | 1 |
| Victor Raider-Wexler | Janitor | Vascular Doctor | 1 | 1 |
| Michael Adler | Handler | Marty, Rick | 1 | 2 |
| Peggy Mannix | Charity Women | Mrs. Breeland, Mrs. Styman | 1 | 2 |
| Charles C. Stevenson Jr. | Lester | Capt. Eddie | 1 | 1 |
| Donna Ponterotto | Waitress | Pearl | 1 | 1 |
| E.J. Callahan | Sid | Drunk | 1 | 1 |
| Francis Guinan | Jedediah | Police Negotiator | 1 | 1 |
| Jeanine Jackson | Claire | Elise Stevens | 1 | 1 |
| Kimberly Scott | Emily | Sandy's Mother | 1 | 1 |
| Lee Ryan | Minister | Ortho #2 | 1 | 1 |
| Lesley Fera | Woman #2 | Helen Kolber | 1 | 1 |
| Lily Knight | Nurse Turner | Mary Cochran | 1 | 1 |
| Michelle Anne Johnson | Receptionist | Sarah Irving | 1 | 1 |
| Peggy Miley | The Columbian | Bird Lady | 1 | 1 |
| Ray Baker | Mr. Demarmel | Durant | 1 | 1 |
| Rif Hutton | Bookstore Guy | Mr. Royston | 1 | 1 |
| Scott Klace | Mark | Chris Halpern | 1 | 1 |
| Sharon Madden | Guest #2 | Risberg | 1 | 1 |
| Sonya Eddy | Ticket Taker | Harriet, Student Affairs Secretary | 1 | 3 |
| Tom Towles | Dale | Teenage Boy's Father | 1 | 1 |
| Lance E. Nichols | Security Salesman | Detective Barnes | 1 | 2 |
| Christopher Holloway | Stage Manager | Mr. Preston | 1 | 1 |
| Elsa Raven | Aunt Florence | Rosemary Smalls | 1 | 1 |
| Gary Carlos Cervantes | Mechanic | Cop | 1 | 1 |
| Jack Hallett | Jury Foreman | Jimmy Vogel | 1 | 1 |
| Jorge Luis Abreu | Ron | Security Guard | 1 | 1 |
| Karen Austin | Anita | Mrs. Carlson | 1 | 1 |
| Lisa Kaminir | Margueritte | Jessie | 1 | 1 |
| Lise Simms | Gabby | Emcee | 1 | 1 |
| Lois Foraker | Patty Muller | Ida Blinnder | 1 | 1 |
| Pat Crawford Brown | Mrs. Larson | Mrs. Votey | 1 | 1 |
| Rick Hall | Limo Driver | Detective in Larkin Case | 1 | 1 |
| Rock Reiser | Spectator | Mr. Dupont | 1 | 1 |
| Ruth de Sosa | Laura | Carla | 1 | 1 |
| Steven M. Gagnon | Cop | Dr. Blum | 1 | 1 |
| Tom Simmons | Peter | Ethan Brown | 1 | 1 |
| Amanda Carlin | Flora | Librarian | 1 | 1 |
| Amy Smallman | Nurse | Myrna | 1 | 1 |
| Cesar Herrera | Manolito | Shirtless Guy | 1 | 1 |
| David Dunard | Mechanic | Irish Guy | 1 | 1 |
| David Kirkwood | Yellin' Joe Slocum | Mr. Reynolds | 1 | 1 |
| Jake Thomas | Kid | Nick Riley | 1 | 1 |
| John Maynard | Customer #2 | Flasher | 1 | 1 |
| Ken Magee | Policeman Joe | Security Guard Manager | 1 | 1 |
| Mark Ankeny | Husband | Electrician | 1 | 1 |
| Tom Kiesche | Large Man | Officer Monroe | 1 | 1 |
| Benjamin King | Man In Bar | Costi | 1 | 1 |
| Cynthia Frost | Aunt Sylvia | Mrs. Fruhman | 1 | 1 |
| Daniel Kountz | Jimmy | Reed Silvan | 1 | 1 |
| Eric Saiet | Pleasant Man | Alex Dibble | 1 | 1 |
| John Craig | Kid | Trent | 1 | 1 |
| Larry Udy | Bailiff | Evidence Tech | 1 | 1 |
| Lorna Scott | Mrs. Walters | Stan's Wife | 1 | 1 |
| Mary-Pat Green | Diane | Miss McDuffy | 1 | 1 |
| Sid Newman | Phelps | Marvin Kloner | 1 | 1 |
| Steven M. Porter | Roger | Mr. Pularski | 1 | 1 |
| Alex Kubik | Counterman | Kurt Vangoss | 1 | 1 |
| Kathryn Joosten | Cafeterial Lady | Lois | 1 | 1 |
| Sean Moran | Ernie | Mr. Blinker | 1 | 1 |
| Wayne Péré | Jonesy | Eric Farve | 1 | 1 |
| Frank Clem | Waiter | Turner | 1 | 1 |
| John Eric Bentley | Todd | Larry Anderson | 1 | 1 |
| Kyle Colerider-Krugh | Elroy | Martin | 1 | 1 |
| Michael McCarty | Santa Claus | Gerry Gugliemotto | 1 | 1 |
| Stephen Rockwell | Attorney #5 | Dr. Morton | 1 | 1 |
| Diana Castle | Saleswoman | Sandy Maggioso | 1 | 1 |
| Lindsey Fields | Louise | Gail | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.