'NCIS' Cast Secrets: Harrison Ford and Jennifer Aniston Among Early Frontrunners

Today is “NCIS Day” in honor of the series’ 20 years on CBS, and the Eye Network is celebrating the occasion with a mini marathon of episodes tonight, starting with the premiere episode, which aired Sept. 23, 2003.

But before the first episode aired, NCIS was a two-episode backdoor pilot on JAG to see if the idea would fly. And because of its connection to JAG, the spinoff was initially intended to be split like Law & Order, with the first half of the hour featuring the NCIS team investigating a crime and the second half focusing on the Navy's Judge Advocate General's (JAG) Corps handling the legal matters after.

But after watching the two episodes, Les Moonves, then head of CBS said, “Why don’t we just make it all investigation?” And that’s what happened.

But first, the series had to be cast and in honor of the anniversary, The Hollywood Reporter spoke with NCIS creators Donald P. Bellisario and Don McGill, as well as fellow executive producer Charles Floyd Johnson, former CBS head of casting Peter Golden, and casting director Susan Bluestein, to get the scoop on how the roles were filled.

Related: CBS Declares 'NCIS Day' in Honor of the Series' 20 Years on Air

Naturally, the key role that had to be cast before anything else was that of Special Agent Leroy Jethro Gibbs, and Bellisario and McGill considered a long list of names prior to Mark Harmon landing the role.

“I know Harrison Ford was a name that everybody thought about for Gibbs because he was so perfect,” Johnson said. “But I don’t think it ever got further than, it was a name thrown out.”

And Golden added, “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.”

Other names that went on the list—but never received offers—were Alec Baldwin, Chris Cooper, Clive Owen, Kevin Bacon, Tom Berenger, Val Kilmer, Charlie Sheen, Aidan Quinn, Scott Glenn and Patrick Swayze.

“Andrew McCarthy at one point was in the mix for Gibbs. He and Don Bellisario met and talked over the role,” McGill told HR.

Then Bluestein added, “Casting was very challenging. I cast Mark Harmon to play John Dillinger in a movie of the week in 1991, and he was terrific. Mark had been on my NCIS list from day one. I always felt like Mark really had the gravitas for this character.”

Feeling as she did about Harmon, Bluestein went to bat for him. She recalls, “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 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.”

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Once the show had its lead, the other key characters needed to be found. In the two-episodes that aired as part of JAG, the character of Kate Todd (Sasha Alexander) didn’t exist. At that point in time in the fictitious world of NCIS, Kate was a member of the Secret Service. It isn’t until the pilot and everything that happens aboard Air Force One that she is forced to resign from the Service, and Gibbs hires her.

Johnson recalls, “Sasha Alexander wasn’t in the two-episode pilot. It was an actress by the name of Robyn Lively. They liked her, but they didn’t think she quite worked. And so, when the series got picked up, CBS said, ‘We’d rather move on.’ And then we went in search of a character, and Sasha came in at the last minute. I loved Robyn Lively, but those things do happen.”

But interestingly, as Johnson relates to HR, Jennifer Aniston was available at the time, and her name was floated.

“I don’t remember ever offering it to Jennifer Aniston,” Bluestein said. “Jennifer Aniston could very well have been a name that we discussed.”

NCIS—or Navy NCIS as it was called in Season 1—landed Alexander, but only for two years. And when she opted not to renew her contract, one of TV’s most shocking moments happened. Kate was killed with a sniper's bullet to her head in the last moment of Season 2.

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Next on the list was the role of Special Agent Tony Di Nozzo. Again, it’s casting director Bluestein who recalls how that went down.

She tells the HR, “I loved Michael Weatherly. But he happened to not be available because he was in Australia [playing Robert Wagner] for The Mystery of Natalie Wood. Don [Bellisario] was also going to Australia and had a place there, and they went out to dinner. And, of course, later on Robert Wagner would end up playing Michael Weatherly’s father in the show, which was really ironic.”

Pauley Perrette was cast as Abby Sciuto because Bellisario wanted the show to have some humor. So, like CSI: Crime Scene Investigation where lab tech Greg Sanders (Eric Szmanda) was the comic relief, the character of Abby was born.

And the final original character for the first season—Sean Murray as Special Agent Timothy McGee only recurred in Season 1—was that of Donald “Ducky” Mallard.

“When they cast David McCallum as Ducky, the studio said, ‘No way, we’re not casting this old character actor in the role,’” recalls James Whitmore Jr., who has directed multiple episodes of the series. “And Don [Bellisario] said, ‘If you don’t, we’re not doing the show.’ He was that serious about it. The studio went with it, and of course, David McCallum is gold.”

The NCIS mini marathon begins airing tonight at 8 p.m. ET/PT with three back-to-back episodes on CBS.

Next, Many Questions Remain as NCIS Heads Into Its 21st Season