All 94 actors in both ER and Mom
94 actors have appeared in both ER and Mom, across 501 episodes. The most-credited is Lyn Alicia Henderson, Paramedic Pamela Olbes in ER and Susan in Mom.
| Actor | In ER | In Mom | Eps | Eps |
|---|---|---|---|---|
| Lyn Alicia Henderson | Paramedic Pamela Olbes | Susan | 149 | 8 |
| Kristen Johnston | Nurse Manager Eve Peyton | Tammy Diffendorf | 6 | 19 |
| Lauri Johnson | Oncology Nurse | Beatrice | 1 | 16 |
| Octavia Spencer | Maria Jones | Regina Thompkins | 1 | 9 |
| Mary Pat Gleason | Anne Parks | Mary | 1 | 8 |
| Sara Rue | Jane | Candace Hayes | 1 | 8 |
| David Krumholtz | Paul Sobriki | Gregory Munschnick | 3 | 5 |
| Mimi Kennedy | Sgt. O'Malley | Marjorie Armstrong | 1 | 7 |
| Joe Manganiello | Officer Litchman | Julian | 4 | 1 |
| Leonard Roberts | Police Officer | Ray | 1 | 4 |
| Bradley Whitford | Sean O'Brien | Mitch | 2 | 2 |
| Wallace Langham | Dr. Melvoin | Jerry | 1 | 3 |
| Diane Delano | Stella Willis, Delores | Leslie | 5 | 1 |
| Michael Angarano | Zack | Cooper | 1 | 2 |
| Nicole J. Butler | Anesthesiologist | Woman #1 | 1 | 2 |
| Amy Pietz | Loren | Rebecca | 1 | 1 |
| Edward Asner | Dr. James McNulty | Jack | 3 | 1 |
| Jack McGee | Rodney McMullen | Frank | 1 | 1 |
| Lauren Bowles | Hannah | Mary | 1 | 1 |
| Richard Schiff | Mr. Bartoli | Robert | 1 | 1 |
| Rebecca Metz | Waitress | Bobbi | 1 | 2 |
| Stacey Travis | Detective Weller | Deborah | 2 | 1 |
| Teddy Vincent | Vivian Nickelby | Woman #4 | 1 | 2 |
| Tracy Vilar | Doris | Lorraine | 2 | 1 |
| Sam McMurray | Mike Landry | Ned | 1 | 3 |
| Sonya Eddy | Harriet, Student Affairs Secretary | Angela | 3 | 1 |
| James Earl | Elgin Gibbs | Dudley | 4 | 1 |
| Lois Smith | Gracie | Claire Dickinson | 4 | 1 |
| Carlease Burke | Policewoman | Nurse Patricia | 1 | 1 |
| Carol Avery | Betty | Mother | 1 | 1 |
| Crista Flanagan | Pam | Beth | 1 | 1 |
| Dan Martin | Lieutenant | Juan | 1 | 1 |
| Deidrie Henry | Nichelle Richardson | Andrea | 1 | 1 |
| J.J. Boone | Lenore Simkins | Charlotte | 1 | 1 |
| John Rubinstein | Dr. Kenner | Professor Addison | 1 | 1 |
| Patricia Belcher | Ward Nurse | Gloria | 1 | 1 |
| Peter Onorati | Officer Nick Napolitano | Wayne | 1 | 1 |
| Sandy Martin | Mrs. Zarian, Sister Helen | Lillian | 2 | 1 |
| Terri Hoyos | Mrs. Corvalan | Soledad | 1 | 1 |
| Tim Bagley | Archie Papion | Dr. LaSalle | 1 | 1 |
| Jack Impellizzeri | Bartender, Man | Fireman #1 | 2 | 1 |
| Maurice G. Smith | Derek, Stanley Sherman | Jordan | 2 | 1 |
| Wayne Wilderson | Dr. Claypool | Dr. Butler | 1 | 2 |
| Amy Farrington | Sandy Mader | June | 1 | 1 |
| Cleo King | Mrs. Davies | Sandy | 1 | 1 |
| David Figlioli | Nolan | Andre | 1 | 1 |
| Gary Kraus | CJ | Ted | 1 | 1 |
| June Squibb | Social Security Daughter | Dottie | 1 | 1 |
| Lamont Thompson | Paul GIlliam | Marcus | 1 | 1 |
| Lewis T. Powell | Workman | Paramedic | 1 | 1 |
| Louise Claps | Mrs. Jenkins | Linda | 1 | 1 |
| Marcus Folmar | Foreman | Fireman #2 | 1 | 1 |
| Mary-Pat Green | Miss McDuffy | Susie | 1 | 1 |
| Michael Dempsey | Mr. Beckwith | Officer Milliner | 1 | 1 |
| Richard Riehle | Mandrake Patient | John | 1 | 1 |
| Rick Overton | Mr. McNamara | Burt | 1 | 1 |
| Shane Blades | Marcus Udesky | William | 1 | 1 |
| Sonia Jackson | Ruthie Newton | Janet | 1 | 1 |
| Stephanie Erb | Mrs. Kinney | Louise | 1 | 1 |
| Stephen Monroe Taylor | Ulney | Darryl | 1 | 1 |
| Jack Guzman | Morgan | Guard | 2 | 1 |
| Amanda Carlin | Librarian | Gloria | 1 | 1 |
| Andrew James Allen | Casey | Jackson | 1 | 1 |
| Asante Jones | Workman #1 | Corey | 1 | 1 |
| Bianca Lopez | Monica | Alice | 1 | 1 |
| Butch Klein | Wynn | Maitre D' | 1 | 1 |
| Christopher Darga | Wilson | Customs Agent | 1 | 1 |
| Christopher Goodman | Andrew | Waiter | 1 | 1 |
| E.J. Callahan | Drunk | Maintenance Man | 1 | 1 |
| Jim Jansen | Neonatologist | Judge Dugan | 1 | 1 |
| Judy Greer | Tildie Mulligan | Michelle | 1 | 1 |
| Karen Huie | Mrs. Cheung | Betty | 1 | 1 |
| Marcus Toji | Binkey | Walter | 1 | 1 |
| Monica Garcia | Benita Escobar | Soledad | 1 | 1 |
| Rudy Moreno | Sal Ramirez | Javier | 1 | 1 |
| K.T. Thangavelu | Dr. Subramanian | Barbara | 2 | 1 |
| Becky O'Donohue | Sophia | GPS Voice | 1 | 1 |
| Bob Rusch | Lillion | Neal | 1 | 1 |
| Carole Gutierrez | Landlady | Winifred | 1 | 1 |
| Carrie Armstrong | Instructor | Carla | 1 | 1 |
| Dale E. Turner | Daniel Harrison | Jerry | 1 | 1 |
| Emily Kosloski | Amanda | Sandra | 1 | 1 |
| Hamilton Mitchell | Guy from Chairs | Jerome | 1 | 1 |
| Patrick O'Connor | CT Surgeon | Minister | 1 | 1 |
| Tom Amandes | David Gardner | Richard | 1 | 1 |
| Tom Virtue | Pares | Martin | 1 | 1 |
| Bob Glouberman | Jeff | Mr. Davenport | 1 | 1 |
| Brenda Ballard | Barb Weston | Old Woman | 1 | 1 |
| David Barrera | Felix Hernandez | Gary | 1 | 1 |
| Duane R. Shepard, Sr. | Janitor | Al | 1 | 1 |
| George Anthony Bell | Second Reporter | Justice of the Peace | 1 | 1 |
| Jim Piddock | Dr. Earl Whitehead | Kenneth | 1 | 1 |
| Alison La Placa | Female Lawyer | Louanne | 1 | 1 |
| Julie Dretzin | Shelly | Wendy | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.