Before playing Admiral Chegwidden, John M. Jackson played Captain West in the film version of A Few Good Men.
Before playing Secretary of the Navy Nelson, Paul Collins played a Pentagon official also named Nelson in Executive Decision.
And Dean Stockwell was the Secretary of Defense in Air Force One.
And Starring: David James Elliott (Harmon Rabb) had the "starring" for all ten seasons, "and John M. Jackson as Admiral Chegwidden" at the end for the eight seasons in which he appeared in the opening titles.
Retired Marine Corps Master Sergeant Matt Sigloch, originally hired for a small part in the Pilot Movie, became the on-set military technical advisor for all the 227 episodes.
Admiral Chegwidden’s replacement as Judge Advocate General in the final 10th season, General Cresswell, is played by actor David Andrews, who is a graduate of Stanford Law School and was a practicing attorney before becoming an actor.
Completely Different Title: JAG has a different title in Sweden because the word Jag in the Swedish language is the first-person pronoun (i.e. I in English.) Coincidently, the movie A Few Good Men also shares the same title: "På heder och samvete", which is a phrase taken from the Swedish witness oath and literally means "by honor and conscience".
Co-Executive Producer (season 2-10) Charles Floyd Johnson has a small recurring part as toxicologist Dr. Bruce Gasden.
The voice of Producer David Bellisario is several times heard through PA systems and communication radios.
Directed by Cast Member: David James Elliott (Harm) directed three episodes: "Lifeline", "Take It Like A Man", and "There Goes The Neighborhood".
DVD Commentary: Only a few episodes in seasons one and two of JAG have audio commentaries and since they were recorded nine to ten years after the episodes were made, they best can be characterized as remembrance style.
Ending Theme: JAG has a different orchestral end theme for its first season. Later seasons used a version of the opening theme.
Fake American: David James Elliott hails from Canada. However, he did become a U.S. Citizen during the show's run.
Harmon Rabb's half brother Sergei Zhukov is played by Canadian Jade Carter. Evidently he won the part over several Russian actors.
A disgruntled Russian submarine captain hired by Al Qaeda is played by Swedish actor Bo Svenson.
American actor Rex Linn plays a Russian KGB officer who speaks English like a native Texan. The in-universe explanation for this is that he grew up in Texas where his parents spied on the U.S. space program.
Foreign Language Title: JAG had only a few: Déjà Vu, Scimitar, Ares, Rendezvous, Pas de Deux, and Posse Comitatus.
Michael and Troyan Bellisario, in addition to being Don Bellisario's kids, appeared here as Mikey Roberts and the daughter of a Naval officer - both would later have roles on NCIS, though as different characters (Chip Sterling and Sara McGee, respectively). A third kid of Bellisario's did even better - Sean "McGee" Murray had two roles, as a Naval ensign accused of raping a Japanese girl (he didn't do it) and as the kid of one of Adm. Chegwidden's girlfriends.
Jeff MacKay who played Corky in another Bellisario series, Tales of the Gold Monkey, plays Bud Roberts's father Big Bud.
Corbin Bernsen of L.A. Law appears in several episodes as Navy Judge, Captain Owen Sebring.
Michele Greene appears in "Head To Toe" as a judge advocate and Lieutenant Colonel in the U.S. Air Force.
Dean Stockwell of Quantum Leap was the series' second Secretary of the Navy, Edward Sheffield, reprising a character from another Bellisario program, First Monday.
Adam Baldwin of Firefly and Chuck fame appears as a Navy SEAL in the show's ninth season - he reprises the role on NCIS, making it doubly awesome.
Actor Richard McGonagle has a recurring role as a judge. He also had a recurring role as another judge on The Practice as well.
Jolene Blalock of Star Trek: Enterprise appears as a Marine in one episode who Bud helps to become an officer. Other Trek alums appear; Andrew Robinson appears twice as a Navy Admiral, while Faran Tahir plays two roles, one in the NCIS pilot episodes.
Bones actress Michaela Conlin appears as a Marine in one episode in Season Nine, "Posse Commitatus", and John M. Jackson and Scott Lawrence later appeared on the same program as Booth's boss and a Voodoo practicioner (though not of the Hollywood Voodoo variety) in post-Katrina New Orleans respectively.
Major League Baseball pitcher Barry Zito appears on an episode as the pitcher of a Navy baseball team who is charged with assault after hitting a Marine player with a pitch in a Navy-Marine baseball game.
In Memoriam: When Trevor Goddard, actor who played Mic Brumby, died in June 2003 the season 9 premiere episode "A Tangled Webb" part 2 ended with one of these showing a clip from "Life or Death" (5.13) of the JAG family singing Mic "Waltzing Matilda" as he left to return to Australia.
Literary Allusion Title: The second season episode "We the People", taken from the U.S. Constitution, although the story is about the Declaration of Independence.
Milestone Celebration: JAG celebrated its 100th episode "Boomerang (Part I)" by filming it on location in Australia, and the 200th episode was a What If?.
Playing Against Type: Faran Tahir initially plays to type when he appears as an Al Qaida-aligned terrorist in the NCIS pilot episodes, but makes a second appearance on the program as a different character, a CIA operative who Harm manages to smuggle out of Libya.
Recycled Script: "Scimitar" in season 1 and "The Black Jet" in season 4 both feature an American service member captured by a hostile government on their soil, subjected to a Kangaroo Court, and ultimately set free by Harmon Rabb.
Retroactive Recognition: Sam Worthington played an Australian sailor in the 60's in the season five episode "Boomerang: Part I".
Romance on the Set: Patrick Labyorteaux (Bud) fell in love with production manager Tina Albanese.
Sleeper Hit: JAG was a sleeper hit which hardly received any press coverage until the fourth season when it entered the top 15 ratings.
West Coast Team: Back in 2005 there were plans for a JAG: San Diego. The concept was introduced in a season ten backdoor pilot episode, but the series never got made.
You Look Familiar: Before playing Sarah Mackenzie, Catherine Bell played a Navy Lieutenant love interest of Harm's who died in the (intended) first season finale. Harm notices this, and is visibly stand-offish towards her at first because of it. In real life, Bell all but begged to be brought back on the show as another character, and the two characters looking identical was utilized.
Another example is with Lt. Loren Singer, whose actress played an assassin in an earlier episode. This, along with Bellisario's kids showing up, suggests a little nepotism, as David James Elliot (Harm) and Nanci Chambers (Singer) are married in real life.
Also, Alexander Kuznetsov appears first in "Cowboys and Cossacks" as Commander Kretchiak, and in later episodes as a different Russian officer named Captain Alex Volkonov (who becomes Harm's Russian analogue throughout the series).
John Walcutt once played a defendant, Caleb Farmer, who was put to death for his crimes, with Mac defending him and Harm prosecuting. Later, he would come back to play Tom Johnson father of the young girl Harm had befriended and seeking to be her legal guardian.
Barry Jenner (Dallas, Star Trek: Voyager) first appeared in "Ares" as the captain of an Arleigh Burke-class destroyer, and later in "Mr. Rabb Goes to Washington" as the asshole ZNN reporter Norman Delaporte.
Jerry Hardin (Deep Throat in The X-Files) first appears as an airplane mechanic in "Full Engagement", and as a Senator in "Impact" (the latter a UFO-themed episode no less).