All 76 actors in both ER and The O.C.
76 actors have appeared in both ER and The O.C., across 423 episodes. The most-credited is Alan Dale, Al Patterson in ER and Caleb Nichol in The O.C..
| Actor | In ER | In The O.C. | Eps | Eps |
|---|---|---|---|---|
| Alan Dale | Al Patterson | Caleb Nichol | 3 | 14 |
| Samaire Armstrong | Tasha | Anna Stern | 1 | 15 |
| Demetrius Navarro | Paramedic Morales | Arturo Diaz | 53 | 1 |
| Shannon Lucio | Johanna Lambright | Lindsay Gardner | 1 | 12 |
| Perry Anzilotti | Dr. Perry (Anesthesiologist), Ed | Mr. Greenberg | 22 | 2 |
| Gary Grubbs | Emmett Chambliss | Gordon Bullit | 1 | 6 |
| José Zúñiga | Eduardo Lopez | Jason Spitz | 2 | 3 |
| Rosalind Chao | Dr. Theresa Chow | Dr. Kim | 1 | 6 |
| Michelle Hurd | Courtney Brown | Ms. Fisher | 6 | 1 |
| Brian McNamara | Gil Brenner | Carson Ward | 1 | 3 |
| Lamont Thompson | Paul GIlliam | Greg Hodes | 1 | 4 |
| Shaun Duke | Detective, Painter | Dr. Henry Griffin | 2 | 4 |
| Julia Ling | Med Student Mae Lee Park, Michelle | Lucy | 5 | 1 |
| Lorna Scott | Stan's Wife | Beatrice | 1 | 2 |
| Michael Adler | Marty, Rick | Jeff Frenkel | 2 | 2 |
| Cynthia Avila | Psych Clerk | Eva Diaz | 1 | 3 |
| Bruno Amato | Sheriff | Archie | 1 | 2 |
| Henri Lubatti | Victor | Henri-Michel de Momourant | 1 | 2 |
| Ruth Williamson | Registry Nurse | Peggy | 1 | 2 |
| Tom Wright | Wharton | Paul Glass | 2 | 1 |
| Kevin West | Robert Sanders | Mr. Bendis | 1 | 2 |
| Patty Onagan | Dolores | Mima | 1 | 3 |
| Alison La Placa | Female Lawyer | Dr. James | 1 | 1 |
| Christopher Cousins | Kyle Kolber | Greg Fisher | 1 | 1 |
| Sven Holmberg | Lars | Gus | 1 | 2 |
| William Abadie | David | Jean Claude | 1 | 1 |
| Jack Guzman | Morgan | Bouncer | 2 | 1 |
| Kim Evey | Hung | Doctor | 1 | 2 |
| Gregory Itzin | Burn Doctor | Steven Herbert | 1 | 1 |
| Matt Barr | Billy | Wes Seifert | 1 | 1 |
| Michael Reilly Burke | Dick White | Tom Wellington | 1 | 1 |
| Richard Herd | Dr. Murphy | Bill "Uncle Shaun" Shaughnessy | 1 | 1 |
| Taivon McKinney | Jenny | Student #2 | 1 | 1 |
| David Stifel | Boz | Bill | 1 | 2 |
| Alain Uy | Burke | Miguel | 1 | 1 |
| Cathy Lind Hayes | Elaine Gasner | Teacher | 1 | 1 |
| Darion Basco | Justin Chang | Andrew | 1 | 1 |
| Diana Gitelman | Ticket Agent | Alien Girl | 1 | 1 |
| Heidi Van Horne | Jolie | Cameo | 1 | 1 |
| Jeffrey Dean Morgan | Firefighter Lorcan | Joe Zukowsky | 1 | 1 |
| John David Conti | Tony Pipitone | Manager | 1 | 1 |
| Juan Ramirez | Enriquez | Cashier | 1 | 1 |
| Matt Williamson | Fireman #1, Ted | Bartender | 2 | 1 |
| Robert Picardo | Abraham Zimble | Bill Merriam | 1 | 1 |
| Tony Denison | Detective Patrie | Bobby Mills | 1 | 1 |
| Don Perry | Dr. Stan Breedlove | Wizened Old Man | 2 | 1 |
| Gina Gallego | Instructor | Eva Diaz | 1 | 1 |
| Kathleen M. Darcy | Judy | Nurse | 1 | 1 |
| Michael Mantell | Mr. Spencer | Jim Mercer | 1 | 1 |
| Shane Haboucha | Barry Kendrick | Eric Ward | 1 | 1 |
| Steven M. Gagnon | Dr. Blum | Arson Investigator | 1 | 1 |
| Deirdre M. Smith | Lauren Nichols | Agent Jill Stonerock | 1 | 1 |
| Dwight Hicks | Officer Hutton | Sheriff | 1 | 1 |
| Gilbert Glenn Brown | Lou Smith | Officer Patrick | 1 | 1 |
| Hamilton Mitchell | Guy from Chairs | Reverend Donahue | 1 | 1 |
| Mark L. Young | Evan Hayes | Prepubescent Geek #1 | 1 | 1 |
| Nancy Linari | Elizabeth Puro | Landlord | 1 | 1 |
| Stephon Fuller | Transport Tech Jim | Photographer | 1 | 1 |
| Carrie Armstrong | Instructor | Diner Cashier | 1 | 1 |
| Charles Rahi Chun | Ben's Dad | Foreclosure Agent | 1 | 1 |
| Kathleen Mary Carthy | Nurse Blake | Dr. Snow | 1 | 1 |
| Phil Abrams | Rodney | Mr. Sheeran | 1 | 1 |
| Taylor Tan | Pharm Girl | Pre Frosh #2 | 1 | 1 |
| Lisa K. Wyatt | Transpo Tech | Customer | 1 | 1 |
| Sandra Marshall | Patron | Samples Lady | 1 | 1 |
| Sean Blakemore | Mario | Trauma Dr. | 1 | 1 |
| Stacy Barnhisel | Nancy | Newpsie | 1 | 1 |
| J.J. Boone | Lenore Simkins | Denise | 1 | 1 |
| Parvesh Cheena | Dr. Agbo | Passerby | 1 | 1 |
| Rigo Sanchez | Vega | EMT | 1 | 1 |
| Stacey Hinnen | Bolog | Gruff Bondsman | 1 | 1 |
| John Maynard | Flasher | State Trooper | 1 | 1 |
| Steve Seagren | Zimmer | Nick | 1 | 1 |
| Ray Laska | Detective Orr | Esbenshade | 1 | 1 |
| Christine Romeo | Mother | Newport Woman #1 | 1 | 1 |
| Joseph Anthony | Scalise | Luis | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.