Creator Donald P. Bellisario served four years in the U.S. Marine Corps and developed a consistent pro-military stance in his shows, having previously worked on Baa Baa Black Sheep and co-created Magnum P.I.
After his series Quantum Leap was cancelled, Bellisario moved to Paramount and began writing a one-shot screenplay about a murder mystery aboard a Navy aircraft carrier, inspired by the introduction of female fighter pilots and the fallout from the Tailhook scandal, which evolved into JAG.
Bellisario chose to center the show on Navy Judge Advocate General lawyers because, unlike other legal dramas, they could alternate between roles of detective, prosecutor, and defender, giving unique storytelling flexibility.
During its NBC season, network executive Don Ohlmeyer pushed for more action and imposed a new female lead, Tracey Needham, replacing Andrea Parker who had starred in the original pilot movie.
After being cancelled by NBC and picked up by CBS, JAG moved its production base at the start of season three from the Paramount lot on Melrose Avenue to Valencia Studios in Santa Clarita to cut soundstage costs, the same facility where NCIS would later be filmed alongside it.
Despite its global setting, JAG was filmed almost entirely on location in Southern California, using local buildings as stand-ins for foreign locations, such as the Park Plaza Hotel doubling for a Moscow hotel and the Shrine Auditorium representing settings in Bahrain and the Middle East.
CGI was increasingly used to remove palm trees and California license plates from shots to help disguise the California filming locations as international settings, and the deception reportedly worked so well that overseas viewers wrote in asking when the show would film in their own cities.
Between July 12–14, 1999, lead actors David James Elliott, Catherine Bell, and Patrick Labyorteaux filmed aboard the real nuclear-powered aircraft carrier USS John C. Stennis for scenes used in the first three episodes of season five.
The Department of Defense initially refused to cooperate with JAG's producers due to sensitivities from the Tailhook scandal, but the production got around this using stock military footage from other Paramount films like Top Gun, The Final Countdown, and The Hunt for Red October; official military assistance began in 1997, with the Marine Corps being more cooperative than the Navy.
Several JAG plots were 'ripped from the headlines,' drawing on real incidents such as the USS Cole bombing, the rescue of downed pilot Scott O'Grady, the Cavalese cable car disaster, the USS Iowa turret explosion, and the Kelly Flinn court-martial case.
JAG served as the backdoor pilot for NCIS via the two-part episode 'Ice Queen'/'Meltdown' in 2003, which was later edited into a one-hour film titled 'NCIS – The Beginning' used to pitch the spin-off to CBS and advertisers; it aired only once and was never released on home video.
The recurring JAG character U.S. Senator Edward Sheffield, played by Dean Stockwell, originated on Bellisario's earlier series First Monday before becoming the Secretary of the Navy on JAG starting in season eight.
JAG was referenced in pop culture crossovers, including a Yes, Dear episode where Catherine Bell and other JAG cast appeared as themselves or their characters, and a Bette Midler sitcom episode featuring David James Elliott in an episode-within-an-episode parody of JAG.
The series finale ends with a challenge coin toss to decide whether Harm or Mac would leave the military, deliberately left unresolved on screen; the outcome was only revealed 14 years later in the 2019 finale of NCIS: Los Angeles season 10.
Slate critic Virginia Heffernan wrote a scathing review calling JAG 'right-wing military propaganda' that operated like 'socialist realist novels,' while the ABA Journal ranked it 13th among the 25 greatest legal TV shows of all time in 2009.
