All 131 actors in both Seinfeld and The Practice
131 actors have appeared in both Seinfeld and The Practice, across 347 episodes. The most-credited is Richard McGonagle, Mr. Star in Seinfeld and Judge Patrick Wilcox in The Practice.
| Actor | In Seinfeld | In The Practice | Eps | Eps |
|---|---|---|---|---|
| Richard McGonagle | Mr. Star | Judge Patrick Wilcox | 1 | 16 |
| James Pickens, Jr. | Det. Hudson | Detective Mike McKrew | 1 | 15 |
| Herb Mitchell | Business Man #1 | Judge Rodney White | 1 | 12 |
| Bruce Davison | Wyck | Scott Wallace | 3 | 9 |
| Anna Gunn | Amy | A.D.A. Jean Ward | 1 | 10 |
| Debra Mooney | Mrs. Sweedler | Judge P. Spindle | 1 | 7 |
| Mik Scriba | Bomb Squad Guy, Cop #1 | Detective Frank Simons | 2 | 6 |
| Reni Santoni | Poppie | Roland Mapp | 4 | 2 |
| Daniel Von Bargen | Kruger | Detective Smiley | 4 | 1 |
| Ernie Sabella | Naked Man | Attorney Harland Bassett | 1 | 4 |
| Stanley Anderson | Judge Arthur Vandelay | Dr. Robert Gale, Dr. Thomas Bellamy | 1 | 3 |
| Ellis E. Williams | Exterminator, Karl | Kevin Beel | 2 | 4 |
| Philip Baker Hall | Lt. Bookman | Judge Joseph Vinocour | 2 | 4 |
| Tim DeKay | Kevin | Jerry Green | 2 | 1 |
| Tony Amendola | Rushdie | Dr. Bernard Gorman, Dr. Alvin Traub, Dr. Emmanuel Willis | 2 | 4 |
| Thom Barry | Manager, Super | Judge B. Watson | 2 | 3 |
| James Hong | Bruce | Min Wong | 1 | 1 |
| James Rebhorn | D.A. Hoyt | Attorney John Rapherson | 2 | 2 |
| Katherine LaNasa | Cathy | Sheila Roe | 1 | 1 |
| Lisa Edelstein | Karen | Diane Ward | 2 | 2 |
| Melinda McGraw | Angela | Marcie Bartos | 1 | 1 |
| Stephen Tobolowsky | Tor Eckman | Clyde Burrows | 1 | 1 |
| David Moreland | Mr. Parry | A.D.A. Matthew Platt, Coroner | 1 | 4 |
| Ken Hudson Campbell | Ken | Roland Huff | 1 | 4 |
| Lane Davies | MacKenzie | Kyle Barrett | 1 | 4 |
| Tucker Smallwood | Malcolm, Man in Mercedes, The Photographer | Dr. Henry Matthews, Dr. Mick Benson | 3 | 2 |
| Armin Shimerman | Stan | Judge Garth Moskin | 1 | 2 |
| Megan Cole | Peggy | Meredith Pearson | 2 | 4 |
| Michael Fairman | Mr. Pensky | Governor's Council Richmond, School Board President Harold Shaw | 1 | 2 |
| James Karen | Mr. Canterman | Judge M. Knapp | 1 | 3 |
| Jeremy Roberts | Chauffer | Alan Neel | 1 | 3 |
| Kate Mulligan | Party Guest, Sheri | Christine Mullin | 2 | 2 |
| Cynthia Ettinger | Michele | Martha Pinker | 1 | 1 |
| David Dunard | Guard, Leader, Security Guard | Judge in Rydell Hearing | 3 | 1 |
| Kevin Dunn | Joel | Bill Munce | 1 | 1 |
| Mark Harelik | Milos | Michael Agosta | 1 | 1 |
| Mark L. Taylor | Michael | Dr. Reichal, Judge Andrew MacDonald, Wiggins' Psychiatrist | 1 | 3 |
| Patricia Belcher | Woman #1 | Candace Levy, Foreperson | 1 | 2 |
| Suanne Spoke | Customer | Sophie Taylor | 1 | 1 |
| Vic Polizos | Tabachnik | Detective Wes Pegler | 1 | 1 |
| David Purdham | Dr. Resnick | Attorney Matthew Stone | 1 | 3 |
| Leon Russom | Clayton | Brian Kearns | 1 | 2 |
| Michael Kagan | Willie | Judge Keller, Peter Martini | 1 | 2 |
| Rick Hall | Vet | Officer Trimble | 2 | 1 |
| Dayton Callie | Cabbie | Francis Lupino | 1 | 1 |
| Doug Ballard | Eddie | Jack Carroll | 1 | 1 |
| Jack McGee | Ralph | Detective Schitt | 1 | 1 |
| Jack Shearer | Mr. Tuttle | Mr. Johnson | 1 | 1 |
| Kelly Perine | Usher | Teddy Maynard | 1 | 1 |
| Langdon Bensing | Man on Street | Bailiff | 1 | 1 |
| Marlee Matlin | Laura | Sally Berg | 1 | 1 |
| Nancy Lenehan | Volunteer | Nurse MacKenzie | 1 | 1 |
| Shashawnee Hall | Usher | Officer Horton | 1 | 1 |
| Denise Dowse | Mother, Receptionist | Caroline | 2 | 1 |
| McNally Sagal | Carol | U.S. Attorney Melnick | 1 | 2 |
| Daryl Keith Roach | Blind Violinist / Cop | Testifying Police Officer | 1 | 1 |
| Earl Boen | Eulogist | Dr. Broadman | 1 | 1 |
| Fred Sanders | John | Roland Hoffstra | 1 | 1 |
| Helen Carey | Mrs. Nyhart | Dr. Kobatch | 1 | 1 |
| Jeff Yagher | John | Michael Sawyer | 1 | 1 |
| Keith Sellon-Wright | Guy | Attorney Berry | 1 | 1 |
| Kymberly Newberry | Ms. Jordan | Susan Kimbro | 1 | 1 |
| Marguerite MacIntyre | Karen | Marcia Willow | 1 | 1 |
| Maurice Godin | Misha | John Aikman | 1 | 1 |
| Mimi Lieber | Rula | D.A. Marcia Scott | 1 | 1 |
| Nancy Linehan Charles | Woman Exec. | Maryann Reynolds | 1 | 1 |
| Ray Proscia | Bobby | Walter Beck | 1 | 1 |
| Taylor Negron | Hairdresser | Mr. Walters | 1 | 1 |
| Debi A. Monahan | Chelsea | Marsha Burns | 1 | 2 |
| Allan Wasserman | Grossbard | James Keplar | 1 | 1 |
| Arabella Field | Miranda | Karen Larson | 1 | 1 |
| Bradford English | Cop | Roland Monroe | 1 | 1 |
| Daniel Dae Kim | Student #1 | Officer Pratt | 1 | 1 |
| Elizabeth Morehead | Noel | Julia Hepler | 1 | 1 |
| Julia Campbell | Lisi | A.D.A. Karen Fields | 1 | 1 |
| Ken Kerman | Officer #2 | Guard | 1 | 1 |
| Mark Roberts | Seth | Security Guard George Reddington | 1 | 1 |
| Rosie Malek-Yonan | Wife | Lambert | 1 | 1 |
| Sayed Badreya | Foreign Man | Adman Fajiz | 1 | 1 |
| Stacey Travis | Holly | Lisa Astin | 1 | 1 |
| Tom La Grua | Kernis | Peter Hynes | 1 | 1 |
| Adrian Sparks | Man | Dr. Maxwell Joseph | 1 | 1 |
| Art Frankel | Bldg 'C' | Pat Magee | 1 | 1 |
| Bill Applebaum | D'Giff | Howard Emerson | 1 | 1 |
| Bill Gratton | Postal Official | Clifford Swanson | 1 | 1 |
| Billy Williams | Usher | Marcus Robbins | 1 | 1 |
| Christopher Darga | Driver | Officer | 1 | 1 |
| Cynthia Madvig | Woman #1 | Brenda Wilbur | 1 | 2 |
| Daniel Zacapa | Power Guy | Mr. Tabbitt | 1 | 1 |
| David Brisbin | Client | Byron | 1 | 1 |
| David Sage | Dr. Dembrow | Judge Robert M. Breech | 1 | 1 |
| James Lashly | Assistant | Joseph Butlington | 1 | 1 |
| James Noah | Ned | Appellate Judge Patterson | 1 | 1 |
| John Capodice | Vic | Joe Jacobs | 1 | 1 |
| Markus Flanagan | Charles | D.A. Earl Schott | 1 | 1 |
| Nick Jameson | Horst | Dr. Tippett | 1 | 1 |
| Rondi Reed | Mary | Suzanne Carroll | 1 | 1 |
| Scott Klace | Guard | Stephen Hatfield | 1 | 1 |
| Wren T. Brown | Walker #2 | Attorney Scott Layden | 1 | 1 |
| Darlene Kardon | Mrs. Lupchek | Mildred the Psychologist | 1 | 1 |
| Eve Brenner | Lady in Restaurant | Sybil Walters | 1 | 1 |
| George Gerdes | Man #1 | Gun Manufacturer | 1 | 1 |
| Jerry Sroka | Todd | Attorney Bob Walsh | 1 | 1 |
| John Cothran, Jr. | Man | Chris Patterson | 1 | 1 |
| Kellie Waymire | Vivian | Dr. Marshall | 1 | 1 |
| Magda Harout | Stella | Jan Jessel | 1 | 1 |
| Marla Fries | Stewardess | Sheila McCree | 1 | 1 |
| Patience Cleveland | Old Lady | Sylvie Tyler | 1 | 1 |
| Patricia Place | Wife | Mary Burlington | 1 | 1 |
| Basil Hoffman | Salesman | Attorney Art Hardiman | 1 | 1 |
| J. Patrick McCormack | Leland | Pierce Stanton | 1 | 1 |
| John Kapelos | Barry | Officer John Rydell | 1 | 1 |
| Larry Braman | Stage Manager | Mark Green | 1 | 1 |
| Richard Roat | Dr. Berg | Dr. Munson | 1 | 1 |
| Brian Reddy | Dan | Dr. Pankin | 1 | 1 |
| Frank Novak | Clerk | Dick Walsh | 1 | 1 |
| Harley Venton | Dan | Mike Randall | 1 | 1 |
| Lou Cutell | Howard Cooperman, MD | Adelstein | 1 | 1 |
| Stephen Caffrey | Arnie | Marty Andleman | 1 | 1 |
| Eric Fleeks | Kicker | Court Officer | 1 | 1 |
| William B. Jackson | Doctor | Judge Watson | 1 | 1 |
| Charley Garrett | Man #1 | Dr. Jeffrey Weinberg | 1 | 1 |
| Clement E. Blake | Dirt Person #1 | Homeless Man | 1 | 1 |
| Mimi Cozzens | Mrs. Canterman | Ellen Rapson | 1 | 1 |
| Wendy Worthington | Louise | Jury Foreperson #1 | 1 | 1 |
| Alison Martin | Lucy | Judy Blair | 1 | 1 |
| Matthew Fonda | NBC Executive | Attorney Joseph Roberts | 1 | 1 |
| Marcelo Tubert | Father | Darryl Stanton | 1 | 1 |
| Shannon K. Dunn | Elaine's Co-Worker | Federal Court Foreperson | 1 | 1 |
| Jeffrey von Meyer | Poker Player #4 | Foreman | 1 | 1 |
| Elayn J. Taylor | Book Fan | Judge Haley Logan | 1 | 1 |
Cast data from TVmaze, licensed CC BY-SA 4.0.