All 117 actors in both American Horror Story and ER
117 actors have appeared in both American Horror Story and ER, across 476 episodes. The most-credited is John Aylward, Father Malechi in American Horror Story and Dr. Donald Anspaugh in ER.
| Actor | In American Horror Story | In ER | Eps | Eps |
|---|---|---|---|---|
| John Aylward | Father Malechi | Dr. Donald Anspaugh | 1 | 74 |
| Lyn Alicia Henderson | Det. Barker | Paramedic Pamela Olbes | 1 | 149 |
| Frances Conroy | Moira O'Hara (Old), Myrtle Snow, Shachath | Becky Riley | 26 | 2 |
| Yvonne Zima | Red | Rachel Greene | 1 | 22 |
| Adina Porter | Beverly Hope, Lee Harris, Sally Freeman | Mrs. Hopkins | 21 | 1 |
| Mare Winningham | Ms. Hazel Evers, Alicia Spencer, Rita Gayheart | Dr. Amanda Lee | 14 | 4 |
| Finn Wittrock | Tristan Duffy, Rudolph Valentino, Jether Polk | Thomas Yoder | 12 | 1 |
| Lisa Vidal | Stacey Ramos | Fire Lieutenant Sandy Lopez | 1 | 12 |
| Mädchen Amick | Mrs. Ellison | Wendall Meade | 3 | 10 |
| Fredric Lehne | Frank McCann | Bum's Friend | 7 | 1 |
| Celia Weston | Lillian Hemmings | Sister Maureen Chapman | 5 | 1 |
| Tara Karsian | Chef Bertie | Liz Dade | 3 | 7 |
| Malaya Rivera Drew | Det. Barrios | Katie Alvaro | 2 | 11 |
| Barbara Tarbuck | Mother Superior Claudia | Alice Presley | 5 | 1 |
| John Lacy | Mikey | Kevin Poole | 2 | 1 |
| Robin Weigert | Real Mama Polk, Coucilwoman Martha Edwards, Cynthia Potter | Nicole | 5 | 1 |
| Matthew Glave | Larry Gayheart | Dr. Dale Edson | 1 | 15 |
| Colby French | Officer | Greg Becton | 4 | 1 |
| Clea DuVall | Wendy Peyser | Katie Reed | 5 | 2 |
| Eric Stonestreet | Derek | Willie | 1 | 1 |
| Kal Penn | Mac Marzara | Narajan | 5 | 1 |
| Morris Chestnut | Luke | Nurse Frank "Rambo" Bacon | 6 | 2 |
| Mitch Pileggi | Art | Terry Waters | 2 | 1 |
| Riley Schmidt | Rubber Man, Orderly | Matt | 8 | 1 |
| Shannon Lucio | Diana Cross | Johanna Lambright | 2 | 1 |
| Lee Tergesen | Vince | Mr. Mullen | 3 | 1 |
| Frederick Koehler | Real Lot Polk | Benjamin Coe | 4 | 1 |
| John Prosky | CEO Frank | Mr. Brooks | 1 | 4 |
| Steven Culp | Brooke's Father | Dave Spencer, Dr. Charles Cameron | 1 | 5 |
| Mike Colter | David | Watts | 3 | 1 |
| Kyle Davis | Dallas | Kyle | 4 | 1 |
| Ameer Baraka | Bastien, Minotaur | Reid | 6 | 1 |
| Dennis Cockrum | Senator Herbert Jackson | Little League Player's Father | 2 | 1 |
| Eve Gordon | Dr. Hall | Mrs. Nugent | 4 | 1 |
| Drew Snyder | Televangelist | Mr. Drane | 3 | 1 |
| Joel McKinnon Miller | Det. Connors | Mr. Emerson | 3 | 1 |
| Tim Russ | David Chambers | Dr. Medford | 1 | 1 |
| Kasey Mahaffy | Father James | Johnny | 2 | 1 |
| Lance E. Nichols | Det. Sanchez | Detective Barnes | 1 | 2 |
| Mary-Pat Green | Nun #1 | Miss McDuffy | 2 | 1 |
| James DuMont | Foster, Dr. Morrison | Clemens | 5 | 1 |
| Eric Nenninger | Security Officer | Psychotic Biting Patient | 1 | 1 |
| Henry G. Sanders | Mr. Royale, Willie | Phillip | 2 | 1 |
| Jim Ortlieb | Ray Cunningham | Cook | 1 | 1 |
| Mena Suvari | Elizabeth Short | Laura-Lee Armitage | 3 | 1 |
| Wayne Péré | Mr. Kingery | Eric Farve | 2 | 1 |
| Lesley Fera | Female Cooperative Agent | Helen Kolber | 1 | 1 |
| Marla Gibbs | Cassie Royale | Cherise Barnes | 1 | 1 |
| Steven M. Gagnon | Golfing Buddy | Dr. Blum | 1 | 1 |
| Tom Virtue | Priest, Principal Johnson, Reporter #1 | Pares | 3 | 1 |
| Andy Umberger | Dr. Day | Dr. David Harvey | 1 | 2 |
| Alessandra Torresani | Stephanie Boggs | Kate Preston | 2 | 1 |
| Eugene Byrd | Grayson's Partner | James Connor | 1 | 1 |
| John Pyper-Ferguson | Mr. Cage | Tom Coggins | 1 | 1 |
| Marco Rodríguez | El Rey | Agent Serena | 1 | 1 |
| Robert Knepper | The Lieutenant | Keith Reynolds | 1 | 1 |
| Steven Anderson | Dr. Marchesi | Dr. Davitch | 1 | 2 |
| Tom Gallop | Mr. Carmichael | Dr. Roger Julian | 1 | 3 |
| Geoffrey Rivas | Det. Jack Colquitt | Haven | 2 | 1 |
| Amy Farrington | Mrs. Reynolds | Sandy Mader | 1 | 1 |
| David Barrera | Dr. Kaplan | Felix Hernandez | 1 | 1 |
| James MacDonald | The Horn | Officer Gary McWayne | 1 | 1 |
| Lara Harris | Rhonda Lancaster | Regina Morgan | 1 | 1 |
| Michael Whaley | Detective | Mr. Busey | 1 | 1 |
| Stefanie Black | Stacey Phillips | Tiffany | 1 | 1 |
| Al Pugliese | Private Eye, Santa | Angelo | 2 | 1 |
| Irene Roseen | Margaret, Molly | Inez | 2 | 1 |
| J. Grant Albrecht | Scott Anderson | ICU Attending, Ronny Faneca | 1 | 2 |
| David Gianopoulos | Det. John Grayson | John Dean / Bob Halderman | 1 | 1 |
| Frederick Dawson | Minister | Bus Driver | 1 | 1 |
| Lorinne Vozoff | Used Bookstore Owner | Marguerite | 1 | 1 |
| Mona Wyatt | Nurse | Eva | 1 | 1 |
| Rebecca Metz | Lorene | Waitress | 1 | 1 |
| Jennifer Jostyn | Ronni | Prosthetist | 1 | 2 |
| Deborah Geffner | Joanna | Mrs. Street | 1 | 1 |
| John Pleshette | Committee Chairman | Stuart | 1 | 1 |
| Lily Knight | Sister Felicity | Mary Cochran | 1 | 1 |
| Scott Lawrence | Det. Webb | Children's Services Rep | 1 | 1 |
| Bob Bancroft | Harry Kirkland | Albert | 1 | 1 |
| Bryan Rasmussen | Hank Stone | Robert Martin | 1 | 2 |
| David Bowe | Detective | Father of Unicycle Boy | 1 | 1 |
| David Naughton | Mr. Samuels | Ben Stevens | 1 | 1 |
| Drew Powell | Det. Collier | Dennis Voltaire | 1 | 1 |
| Kevin Fry | Martin Gamboa | Detective Demetras | 1 | 1 |
| Tom O'Keefe | Frank Sinatra | Danny | 1 | 1 |
| Valorie Hubbard | Mrs. Hindsman | Mrs. Bulowski | 1 | 1 |
| Adam Chambers | Paul Morissey | Chapman | 1 | 1 |
| Alanna Ubach | Jo | Terry's Friend | 1 | 1 |
| Andrew Rothenberg | Mr. Potter | Pauly Johnson | 1 | 1 |
| Gary Kraus | Mack | CJ | 1 | 1 |
| Roxana Brusso | Dr. Kohan | Mari Hinjosa | 1 | 1 |
| Troy Winbush | Newscaster | Uniform Cop | 1 | 1 |
| Lynn Ann Leveridge | Battle-Axe | Sue, Woman | 1 | 2 |
| Ritchie Montgomery | Stunt Zombie #3 | Cahill | 2 | 1 |
| Gwynyth Walsh | Abortion Doctor | Barbara Knight | 1 | 1 |
| Jim Gleason | Dr. Friedman | Little Girl's Father | 1 | 1 |
| Adam Lieberman | Det. Colquitt | Levine | 1 | 1 |
| Al Vicente | Carlos Russell | Luis | 1 | 1 |
| David A. Kimball | Art Auctioneer | tbd | 1 | 1 |
| Sean Blakemore | Male Cooperative Agent | Mario | 1 | 1 |
| Dean Cameron | Reporter #2 | Edward | 1 | 1 |
| Monnae Michaell | Judge | Mrs. Bell | 1 | 1 |
| Tonea Stewart | Cora (Old) | Pearl | 1 | 1 |
| Barbara Lee Bragg | Sheik's Mother | Giselle | 1 | 1 |
| Deborah Pollack | Nurse | Margo | 1 | 1 |
| Helen Eigenberg | Nurse | Renee Weber Stewart | 1 | 1 |
| Marilyn O'Connor | Molly | Mrs. Skapinski | 1 | 1 |
| Rif Hutton | Elder #3 | Mr. Royston | 1 | 1 |
| Roz Witt | Daphne | Saleswoman | 1 | 1 |
| Stacy Highsmith | Grace | Sarah Reid | 1 | 1 |
| Cheyenne Wilbur | Professor | Garrity | 1 | 1 |
| Jon Paul Burkhart | Percy | Fred | 1 | 1 |
| Betty Murphy | Sally Starns | Nancy | 1 | 1 |
| Yolanda Snowball | ICU Nurse | Neighbor | 1 | 1 |
| Betsy Baker | Juror #5 | Dr. Wheeler | 1 | 1 |
| Ric Sarabia | Crazed Man | Drunk | 1 | 1 |
| Linda Porter | Mary | Inga Paulson | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.