All 100 actors in both NCIS and Will & Grace
100 actors have appeared in both NCIS and Will & Grace, across 754 episodes. The most-credited is Tom Gallop, Victor Sterling in NCIS and Rob in Will & Grace.
| Actor | In NCIS | In Will & Grace | Eps | Eps |
|---|---|---|---|---|
| Tom Gallop | Victor Sterling | Rob | 1 | 17 |
| Jamie Kaler | Christopher Bell | Gary | 1 | 5 |
| Livia Treviño | Lupe | Mrs. Timmer | 1 | 5 |
| Mary Pat Gleason | Nurse Wells | Bridget, Sally | 1 | 4 |
| Taye Diggs | Marine Gunnery Sergeant Aaron Davis | James Hansen | 1 | 4 |
| Jon Cryer | Dr. Cyril Taft | Jon Cryer | 3 | 1 |
| Lily Tomlin | Penelope Langston | Margot | 1 | 2 |
| Ben Reed | Chief P.O. Ian Goetz | Richard Keller | 1 | 1 |
| Erinn Hayes | Wendy Hill | Katherine Fallon | 1 | 1 |
| Gary Grubbs | Coroner Elmo Poke | Harlin Polk | 1 | 1 |
| Ivar Brogger | Simon Katz | Mr. Hutt | 1 | 1 |
| Jackie Geary | NCIS Agent Susan Grady | Cashier | 3 | 1 |
| Mark Harelik | Ron Levinson | Tim | 1 | 3 |
| Pej Vahdat | Nigel Hakim, Balesh Sassnid | Steve | 3 | 1 |
| Phil Morris | Navy Capt. Paul Martino | Dr. Norman | 1 | 1 |
| Raphael Sbarge | Rupert Kritzer | Alex | 1 | 1 |
| Reiley McClendon | Marine Private Brad Sykes | Nixon | 1 | 1 |
| Robert Curtis Brown | Gary Tolin | "Will" actor | 1 | 1 |
| Tony Pasqualini | Man | Man | 1 | 1 |
| Jack McGee | Det. Floyd, Richard "Rick" Jordan | Officer Murphy | 2 | 1 |
| John O'Brien | Bruce | Man, Salesperson | 1 | 2 |
| Kevin Sizemore | M.P. Mueller, Marine Sgt. Moore, Stuart Greco | Young Man | 3 | 1 |
| Andy Favreau | CIA Officer Jim Hillcot, Navy Lieutenant Eric Kutzler | JJ Wise | 2 | 1 |
| Ben Giroux | Tiny Tony | Grief Panda | 1 | 1 |
| Brian Howe | Sherriff Tom Barrett | Ken | 1 | 1 |
| Dean Cameron | Building Owner | Guy | 1 | 1 |
| Gina Hecht | Christine Newhall | Amy | 1 | 1 |
| Jeff Witzke | Attendant | Glenn | 2 | 1 |
| Jim Rash | Dr. Joel Sanderson | Brent | 1 | 1 |
| Ken Lerner | Albert Hencheck | Bob | 1 | 1 |
| Larry Poindexter | Dr. Berman | Dan | 1 | 1 |
| Larry Sullivan | Flight Surgeon | Robert | 1 | 1 |
| Lee Garlington | Mary Hanlan | Annette | 1 | 2 |
| Mark Ankeny | Barry Kester | Ted Farmer | 1 | 1 |
| Markus Flanagan | Navy Commander Mike Taffet | Dr. Loranger | 1 | 1 |
| Matt Cook | CID Agent Dolan Thompson | Ross | 1 | 1 |
| Matt Crabtree | Curt Carver | Stage Manager | 1 | 2 |
| Matthew Glave | Navy Commander John McGee | Kirk | 1 | 1 |
| Patrick Fabian | Ray Vincent | Alan | 1 | 1 |
| Steve Valentine | Miles Wolf | Kai | 1 | 1 |
| Sunkrish Bala | Sameer Aziz | Gerald | 1 | 1 |
| Winston Story | Manny | Rex | 1 | 1 |
| Barrett Foa | Tech Operator Eric Beal | Paul | 2 | 1 |
| Randy Vasquez | ATF Special Agent Philip Caffey, NCIS Agent Roger Voight | Ron | 2 | 1 |
| Alexa Nisenson | Young Harriet | Young Karen | 1 | 1 |
| Christopher Darga | Skip Harris | Officer Kirk | 1 | 1 |
| Emil Beheshti | FBI Agent Dan Lenroff | Mike | 1 | 1 |
| Eric Allan Kramer | Phillip Ekkerly | Barry | 1 | 1 |
| Harry Van Gorkum | Alton Brinkman | Porcelain Paul | 1 | 1 |
| James Black | Gate guard | Anthony Dukane | 1 | 1 |
| Karl T. Wright | John Hicks | Wayne | 1 | 1 |
| Kenneth Tigar | Diggar Aldridge | John | 1 | 1 |
| Keone Young | Lee Sung | Owner | 1 | 1 |
| Lori Alan | Warden Diana Tully | Jean | 1 | 1 |
| Marianne Muellerleile | Nurse Hannah Dunstan | Jodie | 1 | 1 |
| Melonie Mack | Jenny Page | Naomi | 1 | 1 |
| Nicola Lambo | CGIS Special Agent Amanda Graham | Angela | 1 | 1 |
| Oliver Muirhead | Jay Danorth | Walter | 1 | 1 |
| Peter MacKenzie | Jack Murdoch | Mean Guy | 1 | 1 |
| Reggie Hayes | Mike Batowski | Dr. Osher | 1 | 1 |
| Robert Clendenin | Pharmacist | Bob Dent | 1 | 1 |
| Sara Paxton | Amber Carnahan | Melanie | 1 | 1 |
| Shohreh Aghdashloo | Mariam Bawali | Pam | 1 | 1 |
| Timothy Davis-Reed | Edison Rawls | Customs Officer | 1 | 1 |
| Robert Costanzo | Jimmy Napalitano | Paul | 1 | 2 |
| Aaron Lustig | Doctor Victor Kalsa | Marv Buhl | 1 | 1 |
| Andy Comeau | M.P.D. Detective Tom Logan | Andy Fellner | 1 | 1 |
| Brian Michael Jones | NCIS Probationary Agent Terry Mahler | Joe | 1 | 1 |
| Karina Bonnefil | Alexis | Genevieve | 1 | 1 |
| Kim Robillard | Dwayne Parker | Brent | 1 | 1 |
| Kirk Baltz | Bob Sweeney | Glenn Gabriel | 1 | 1 |
| Lyn Alicia Henderson | ER Nurse | Nurse | 1 | 1 |
| Martin Morales | Bellman | Employee | 1 | 1 |
| Nathan Anderson | Luke Walters | Andrew | 1 | 1 |
| Rebecca Lowman | Navy Lieutenant Lisa Mason | Pamela | 1 | 1 |
| Steven W. Bailey | Dexter Murphy | Vin | 1 | 1 |
| A.J. Castro | Seal Team Leader | Elias | 1 | 1 |
| Barry Livingston | Bartholomew Lemming | Vince | 1 | 1 |
| Cheryl White | Rebecca Biddle | Cheryl Bricker-Fossberg | 1 | 1 |
| Fred Cross | Roland Pulvino | Curtis | 1 | 1 |
| Gerald Downey | Navy Cmdr. Ray Trapp | Student Nurse Clark | 1 | 1 |
| Helen Eigenberg | Lt. Cmdr. Amanda Wilkerson | Vicky | 1 | 1 |
| James Huang | Petty Officer Wong | Male Passenger | 1 | 1 |
| Jocelyn Ayanna | Asabe Dawson | Ceecee | 1 | 1 |
| Peter Graham | Christopher Crane | Trevor | 1 | 1 |
| Stephanie Erb | Rachel Nasry | Mona | 1 | 1 |
| Will Radford | Dale Gruber | Henry | 1 | 1 |
| Amari O'Neil | Edgar | Felix | 1 | 1 |
| Andy Umberger | FBI Agent Freedman | Captain | 1 | 1 |
| Brad Grunberg | Big Ed | Ralph | 1 | 1 |
| Christopher Gartin | Jason Tupperman | Desmond | 1 | 1 |
| Dan Warner | Federal Marshal | Doug | 1 | 1 |
| Fareed Ward | JSOC Navy Lieutenant Eric Kagen | Guy #1 | 1 | 1 |
| Matt Champagne | Doctor | Don | 1 | 1 |
| Scott Beehner | Milton | Donald | 1 | 1 |
| Sterling Sulieman | NCIS Special Agent Emil Mineoux | Ryan | 1 | 1 |
| Zack Weinstein | Judd Dempsey | Ryan | 1 | 1 |
| Ken Luckey | John Kendall | Man | 1 | 1 |
| Richard Wharton | Squeegee Man | Gerald | 1 | 1 |
| Jamison Jones | Gelfand | Phil | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.