Summary
NCISactors Mark Harmon (Leroy Jethro Gibbs) and Rocky Carroll (Leon Vance) go way back, even further than their extended time together in thecast ofNCIS. Mark Harmon has appeared as Jethro Gibbs sinceNCISoriginated as a backdoor pilot on the legal dramaJAG.Rocky Carroll joined the show as NCIS Director Leon Vance a little while later inNCISseason 5, making him the show’s longest-standing NCIS director. While both actors have a track record as mainstays on the show for nearly two decades, respectively, their familiarity with each other predates the police procedural.
Both actors remain paramount toNCIS. Rocky Carroll will return totheNCISuniversein the main series as it airsNCISseason 22. His character was central to events in theNCISseason 21 finale. Mark Harmon will return for a separate project, playing a vital role in an upcoming spinoff. While new series and existing spinoffs inevitably draw attention to new actors and characters, Jethro Gibbs and Leon Vance have stood in the vortex of all that’s unraveling. Even more impressive is thatthe history between these two actors predates theirNCISlegacies.

Mark Harmon & Rocky Carroll Both Appeared In Chicago Hope
Chicago Hope Aired For Six Seasons From 1994 To 2000
Mark Harmon and Rocky Carroll both appeared in the late ’90s medical dramaChicago Hopebefore they were cast inNCIS.The actors have a similar track record in the medical series, appearing in 95 and 96 episodes, respectively, between 1996 and 2000. The series centered around the professional and personal lives of the hospital staff at Chicago Hope Hospital. The series comprised an outstanding cast, including Mandy Patinkin as Dr. Jeffrey Geiger. Mark Harmon portrayed Dr. Jack McNeil, an orthopedic surgeon, and Rocky Carroll portrayed emergency room physician Dr. Keith Wilkes.
In the series, Harmon’s Dr. McNeil has the same no-nonsense attitude as Leroy Jethro Gibbs. He is one of the series' more headstrong doctors. He often commands a situation by instructing those around him to help save lives and is known to take his work seriously. Rocky Carroll’s Dr. Keith Wilkes is more mild-mannered and doesn’t have nearly the same leadership prowess as he does inNCIS.That said,Harmon’s role inChicago Hopewas a precursor to his character onNCIS,whereas Carroll’s role in the police drama was more of an evolution from the medical drama.

In an interview withTVLine, Carroll credited Mark Harmon with securing his role in theNCIScast. He said,“I tell people all the time I only knew one person connected to NCIS, but it was the right person to know, and that was Mark Harmon.”
Mark Harmon & Rocky Carroll’s NCIS Characters Are Competing For A Franchise Record
Jethro Gibbs & Leon Vance Are The Top Competitors For The Franchise’s Most Expansive Character
The actor’s futures are just as entangled as their pasts. Mark Harmon and Rocky Carroll are the two major players in the competition for who has madethe most appearances in theNCISfranchise. Rocky Carroll’sLeon Vance has been featured in fourNCISseries, including his 17-season stay on the original show. He also appeared as the NCIS Director inNCIS: Los Angeles, NCIS: New Orleans,andNCIS: Hawai’i.Carroll’s character is expected to be omnipresent in the franchise, since Vance oversees all the NCIS offices as the agency’s director and is responsible for supervising each NCIS team.
Harmon also has an impressive presence in theNCISfranchise. Harmon’s Jethro Gibbs appeared inNCIS, NCIS: New Orleans,andJAGas the Special Agent in Charge at NCIS Headquarters. Harmon’s appearances on manyNCISshows understate thatMark Harmon is synonymous withNCIS. His character is not as essential to the narrative as Rocky Carroll’s but appears throughout the franchise regardless.Gibbs will return toNCISin theNCIS: Originsspinoff, making Gibbs' reach in the franchise as extensive as Vance’s. Both characters can expand their legacies in the future.

Mark Harmon & Rocky Carroll Have Different Futures In The NCIS Franchise
Harmon Will Return To NCIS: Origins And Carroll Will Appear In NCIS Season 22
Two decades after the originalNCISshow kicked off,both actors remain central toNCIS. Mark Harmon will finally return to the franchise after his departure inNCISseason 19 to executive produceNCIS: Origins, though he won’t be part of theNCIS: Originscast. The expansion spinoff will explore the backstory of Harmon’s centralNCIScharacter, winding back the clock to the 1990s when Gibbs was just getting started at the NCIS Camp Pendleton office. Harmon will have a hand in production as executive producer and narrate the series in a similar format to Jim Parsons' narration ofYoung Sheldon.
Rocky Carroll will return forNCISseason 22 as NCIS director, solidifying his character’s central role in the ever-expandingNCISuniverse. AlthoughVance’sNCISdirector role is shrinkingbecause of the cancelation of location-based spinoffs that could otherwise feature his character, Carroll’s role remains vital to the coreNCISnarrative.Carroll will likely make his first appearance inNCIS: Sydney,the remaining location-centered spinoff since the series opted not to feature him in season 1. Director Vance could also appear inNCIS: Tony & Ziva,since he previously worked with both agents and could provide support.
While Chicago Hope would eventually succumb to the competition fromER,NCISwould go on to redefine the police procedural genre
While their characters have an extensive history onNCIS,Harmon and Carroll’s history predates that. Mark Harmon and Rocky Carroll appeared as doctors in Chicago Hope in the late ’90s, and the actors' connection from the show would reunite them onNCIS. They would dominate not just the original series but the entireNCISfranchise. While Chicago Hope would eventually succumb to the competition from ER after six seasons,NCISwould go on to redefine the police procedural genre on CBS. Both performers have been at the center of the franchise’s success.
NCIS
Cast
NCIS is a television series that follows a team of special agents from the Naval Criminal Investigative Service. Premiering in 2003, the show explores various cases involving Navy and Marine Corps personnel, ranging from murder and espionage to terrorism and stolen submarines.