All 96 actors in both Quantum Leap and Seinfeld
96 actors have appeared in both Quantum Leap and Seinfeld, across 275 episodes. The most-credited is Heidi Swedberg, Valerie Nevsky in Quantum Leap and Susan Ross in Seinfeld.
| Actor | In Quantum Leap | In Seinfeld | Eps | Eps |
|---|---|---|---|---|
| Heidi Swedberg | Valerie Nevsky | Susan Ross | 1 | 27 |
| Richard Herd | Moe Stein | Wilhelm | 2 | 12 |
| Patrick Warburton | Blaster | David Puddy | 1 | 10 |
| Warren Frost | Senator Weitzman | Mr. Ross | 1 | 5 |
| Reni Santoni | Staff Sergeant Lopez | Poppie | 1 | 4 |
| Brian George | Ben | Babu Bhatt | 1 | 3 |
| John D'Aquino | Frank LaMotta | Todd Gack | 3 | 1 |
| Teri Hatcher | Donna Eleese | Sidra | 1 | 3 |
| Kevin Page | Young Doctor | Stu Chermack | 1 | 6 |
| Michael D. Roberts | Isaac King, Willis Tyler | Roger Ipswich | 2 | 1 |
| Montrose Hagins | Matty | Old Woman, Woman in Theatre | 1 | 2 |
| Rance Howard | Doc Graves | Blind Man, Farmer | 1 | 2 |
| Susan Diol | Beth Calavicci | Audrey | 2 | 1 |
| Teri Austin | Dana Barrenger | Ava | 1 | 2 |
| Tracy Kolis | Lisa | Kelly, Marlene | 1 | 2 |
| Vaughn Armstrong | Father | Lt. Coleman | 1 | 2 |
| Angelo Tiffe | Carl Morgan | Delivery Man | 1 | 1 |
| Anna Gunn | Liz Lindhurst | Amy | 1 | 1 |
| Claude Earl Jones | Captain Elias | Mr. Bevilaqua | 1 | 1 |
| J.G. Hertzler | Weathers Farrington | Director | 1 | 1 |
| John Kapelos | Dr. Mustafa El Razul | Barry | 1 | 1 |
| Jon Gries | Flash McGrath, Roscoe | Homeless Man, Rusty | 2 | 2 |
| Julio Oscar Mechoso | Raul Casta | Julio | 1 | 1 |
| Marcia Cross | Stephanie Heywood | Dr. Sara Sitarides | 1 | 1 |
| Mark Boone Junior | Mad Dog | OTB Patron | 1 | 1 |
| Melinda McGraw | Laura Downey | Angela | 1 | 1 |
| Elizabeth Dennehy | Beth Ryan | Allison | 1 | 2 |
| Frances Bay | Millie Reynolds | Mabel | 1 | 3 |
| Stephen Lee | Bo Loman | Conrad | 3 | 1 |
| Anita Barone | Debbie Schaefer | Gail | 1 | 1 |
| Bill Erwin | Mr. Deever | Sid | 1 | 2 |
| Chaim Jeraffi | Ali | Jiffy Dump Guy, Jiffy Park Guy | 1 | 2 |
| John Christian Graas | Small Boy | Matthew | 1 | 2 |
| Judy Kain | Waitress | Lorraine | 1 | 1 |
| Louis Mustillo | Mario | Phil | 1 | 1 |
| Michael Fairman | Judge Mulhearn | Mr. Pensky | 1 | 1 |
| Nancy Lenehan | Colleen McBain | Volunteer | 1 | 1 |
| Sherman Howard | Hank Rickett | Roy | 1 | 1 |
| Stephen McHattie | Stawpah | Dr. Reston - the Psychiatrist | 1 | 4 |
| Stephen Root | John Tremaine Jr. | Mr. Lager | 1 | 1 |
| Valerie Mahaffey | Mary Greely | Patrice | 1 | 1 |
| Henry Woronicz | Martin | Father Curtis | 1 | 2 |
| Mary Scheer | Other Woman | Joan, Ms. Smoth | 1 | 2 |
| Peter Murnik | Welles | Lt. Martel | 1 | 2 |
| Susan Isaacs | Lucy Means, Myra Sammis | Woman | 2 | 1 |
| Charles Emmett | Officer Arden | Orderly | 1 | 1 |
| David Sage | Judge | Dr. Dembrow | 1 | 1 |
| Ernie Sabella | Manny | Naked Man | 1 | 1 |
| John Apicella | Sheriff Dixon | Repairman | 1 | 1 |
| Joseph Malone | Deputy Grimes | Michael | 1 | 1 |
| Lewis Arquette | Father Muldooney | Leapin' Larry | 1 | 1 |
| Neil Giuntoli | Private Ryder | Brody | 1 | 1 |
| Ralph Bruneau | Head Steward | Roy | 1 | 1 |
| Tom La Grua | Joey | Kernis | 1 | 1 |
| Wayne Tippit | Henry Mackenzie | Captain | 1 | 1 |
| Elena Wohl | Naomi | Sandi Robbins (Elaine) | 1 | 2 |
| Arthur Rosenberg | Jim McBain | Judge | 1 | 1 |
| Clive Rosengren | George O'Bannon | Mr. Clotworthy, Waiter | 1 | 2 |
| David Graf | Sheriff Nolan | Cop #2 | 1 | 1 |
| David Powledge | Luther | Fan #2 | 1 | 1 |
| Ellen Albertini Dow | Grandma | Momma | 1 | 1 |
| Jan Eddy | Benny Skyler, Whittler | Fan #3 | 2 | 1 |
| Jeanine Jackson | Kelly | Roxanne | 1 | 1 |
| Jed Mills | Monroe | Joel | 1 | 1 |
| O'Neal Compton | Sheriff Russell | Earl | 1 | 2 |
| Richard McGonagle | Bill Wilson | Mr. Star | 1 | 1 |
| Terri Hanauer | Irene Basch | Julianna | 1 | 1 |
| Christine Cattell | Mimi | Stewardess | 1 | 1 |
| Donald Gibb | Violent Protestor | Letter S in Devils Body Painter | 1 | 1 |
| Ernie Lively | Col. Deke Grimwald | Zeke | 1 | 1 |
| Jeanette Miller | Old Lady | Old Woman | 1 | 1 |
| Joe Farago | Cinematographer | Man with Woman | 1 | 1 |
| Leonard Lightfoot | Officer Little | Clyde | 1 | 1 |
| Norman Large | Dirk Simon | Detective | 1 | 1 |
| Mik Scriba | Coach Donnelly | Bomb Squad Guy, Cop #1 | 1 | 2 |
| Cheryl Francis Harrington | Young Woman | Waitress | 1 | 1 |
| Daniel Zacapa | Officer Montero | Power Guy | 1 | 1 |
| Ellen Gerstein | Woman | Carol | 1 | 1 |
| James F. Dean | Dr. Blaustein | Larry | 1 | 1 |
| Myra Turley | Delores | Foreman | 1 | 1 |
| Tim De Zarn | Stan | Salesman | 1 | 1 |
| Brian Leckner | Frat Boy | Attendant | 1 | 1 |
| Diana Bellamy | Mrs. Sherilyn Stanton | Mrs. Ricardi | 1 | 1 |
| Layne Beamer | Tom Stratton | Father | 1 | 1 |
| Lewis Dauber | Reporter | Doorman | 1 | 1 |
| Magda Harout | Mrs. Miriam Dalwitz | Stella | 1 | 1 |
| Maggie Egan | Margaret Cole | Ticket Clerk | 1 | 1 |
| Nigel Gibbs | Waiter | Tenant #2 | 1 | 1 |
| Dale Harimoto | Newscaster | Reporter | 1 | 1 |
| Fitz Houston | Black Senator | Cop | 1 | 1 |
| Tom Verica | Impala | Doctor | 1 | 1 |
| Eve Brenner | Madeline | Lady in Restaurant | 1 | 1 |
| Frank Novak | Lou | Clerk | 1 | 1 |
| Juan Garcia | Jorge | Jaime | 1 | 1 |
| Dean Fortunato | Father Sebastian | Manager | 1 | 1 |
| Beth Aylward | Sarah | Vomit Girl | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.