Actors Who Were Considered To Play NCIS' Gibbs Before Mark Harmon

In hindsight, it's impossible to imagine anyone but Mark Harmon in the role of gruff "NCIS" boss Leroy Jethro Gibbs. It wasn't exactly a career-reigniting role for the actor, who had already built a legacy on shows like "St. Elsewhere"  and "Chicago Hope" before joining the CBS military police procedural's inaugural 2003 season. However, it soon became apparent that Gibbs would be his defining role. Harmon embodied the character in a way that made him the unquestionable centerpiece of the ensemble cast throughout his 19 seasons with the show. He left "NCIS" in 2021, but Gibbs perseveres: In 2024, CBS rolled out the prequel show "NCIS: Origins," with Austin Stowell playing young Gibbs while Harmon narrates, "Young Sheldon"-style. 

Knowing Harmon's importance to the "NCIS" franchise, it may be surprising to find out that the people behind the show didn't call his agent the second they conceived the character of Gibbs. In 2023, the makers of "NCIS" discussed the show's storied history with The Hollywood Reporter, and ex-head of CBS casting Peter Golden revealed that Harmon's name only came up after several other candidates, when casting director Susan Bluestein suggested him:

"Susan said, 'What about Mark Harmon?' Mark was a big deal, and everybody thought, 'We'll make an offer to Mark Harmon, and when we don't get him, let's go through the list of who else we could get.' Mark had a meeting with ['NCIS' co-creator] Don Bellisario, and they hit it off, and Mark agreed to do it. All of a sudden, the show took on much more importance in my mind."

While Harmon was certainly a catch thanks to his status as a successful actor, the original plan was to soar even higher. The first truly major Leroy Jethro Gibbs candidate "NCIS" homed in on was none other than Scott Glenn. A bona fide movie actor who often appeared in multiple films per year and had titles like "Silence of the Lambs" and "Training Day" in his résumé, going for Glenn was a bold swing for a TV show at a time when it was still uncommon for big screen actors to "downgrade" to TV projects. Nevertheless, Susan Bluestein told the Hollywood Reporter that the "NCIS" people were very interested in casting Glenn — either as Gibbs, or as the show's eccentric medical examiner Donald "Ducky" Mallard. 

"Scott Glenn, yes. And Scott Glenn was also being considered for the role of Ducky. There was a lot of discussion about Scott Glenn, and ultimately Scott Glenn passed. And other people passed for Gibbs."

Though Glenn as Gibbs wasn't meant to be, the actor — who started his career in 1960s television — eventually ended up reincorporating small screen work in his repertoire with a string of mid-2000s TV movies. In the 2010s, Glenn has worked primarily in TV projects, playing the blind martial arts master Stick in Marvel's Defenders Saga shows, Kevin Garvey Sr. on "The Leftovers," and Alan Pangborn on "Castle Rock." As for Ducky Mallard, the role ultimately went to "The Man from U.N.C.L.E." actor David McCallum, who stayed with "NCIS" until his death in 2023.

Scott Glenn wasn't even the most impressive name the makers of "NCIS" considered to play Leroy Jethro Gibbs before they waltzed off to make procedural history with Mark Harmon. In the Hollywood Reporter's story, Bluestein mentioned a series of unnamed "other people" who passed the role, but the truly interesting casting ideas came at an early planning stage. At this point, "NCIS" was considering some outright shocking names, including an early favorite: the one and only Harrison Ford. 

The "NCIS" folks quite justifiedly felt that Ford could be a magnificent choice to portray Gibbs, but in all fairness, they were also quite aware that their odds against actually getting the guy were astronomical. As Peter Golden described the process:

"[On] Harrison Ford — when you sit down, and you have an initial conversation about casting, no name is off the table. Back in the early 2000s, the Harrison Fords of the world [rarely did TV]. But that didn't mean you didn't put them on the list."

As Bluestein explained, the "NCIS" team took a spitballing approach when it came to early casting ideas. Since their brainstorming process had very few holds barred, the whiteboard for the early Leroy Jethro Gibbs wishlist included quite a few extremely familiar names, even though Bluestein and others never actually ended up reaching out to them all:

"There were names like Alec Baldwin, Chris Cooper, Clive Owen, Kevin Bacon, Tom Berenger, Val Kilmer, Charlie Sheen, Aidan Quinn, Patrick Swayze. We did not make offers to those people. We just investigated."

While a parallel reality where the NCIS Major Case Response Team is governed by Kevin Bacon or Charlie Sheen (or, indeed, Harrison Ford) while Scott Glenn plays Ducky does sound fascinating, the fact that the show ultimately landed on Harmon — and that Harmon accepted the offer — worked extremely well for everyone involved. Even so, this look into the casting process of what became a successful and long-running procedural series sheds light on the lengthy and often difficult casting process a show has to undertake long before the cameras start rolling.