Long before NCIS became one of television’s biggest success stories, Mark Harmon received a memorable piece of advice from legendary actor Bob Newhart—words that have stayed with him throughout his career. 🎬 Years later, an NCIS executive producer has revealed exactly what Newhart told Harmon, giving fans a rare glimpse into the wisdom that helped shape one of TV’s most iconic leading men.

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‘NCIS’ EP Reveals Bob Newart’s Advice for Mark Harmon

Michael Weatherly, Bob Newhart and Mark Harmon — 'NCIS' Season 8
Sonja Flemming/CBS

What To Know

  • Executive producer Scott Williams joined the latest episode of the NCIS: Partners & Probies podcast.
  • He revealed the advice that Bob Newhart offered Mark Harmon and that he himself took as well.

It didn’t take too long for NCIS to become a hit, and it remains one to this day, heading into its 24th season this fall on CBS. Even in the earlier seasons, those working on it and even guest-starring could see it was something special.

That Time Mark Harmon Got An F-Bomb-Laced Piece Of Advice From NCIS Guest Star Bob Newhart

Executive producer and writer Scott Williams detailed one such moment in the Tuesday, June 30, episode of the NCIS: Partners & Probies podcast when he sat down with its hosts and series stars Brian Dietzen (Dr. Jimmy Palmer) and Diona Reasonover (Kasie Hines).

He recalled that when Bob Newhart guest-starred as Dr. Walter Magnus, the mentor to Dr. Donald “Ducky” Mallard (David McCallum) in the Season 8 episode “Recruited,” he offered Mark Harmon (who starred as Leroy Jethro Gibbs for 19 seasons and remains an executive producer) some advice.

That Time Mark Harmon Got An F-Bomb-Laced Piece Of Advice From NCIS Guest Star Bob Newhart | Cinemablend

“He just said in that very halting Bob Newhart [way], ‘Uh, hey, Mark, can I give you some advice?’ He’s like, ‘Sure, Bob, what is it?’ He goes, ‘Ride this f**ker into the ground,’” Williams shared. “And I heard that. He goes, ‘Jobs don’t get better than this. You will miss this when it’s gone. Seriously, this is like, you’ve struck gold here.’”

That was advice that Williams took as well; he remains an executive producer and writer on the series going into Season 24. “When I heard that, I was like, ‘I am gonna do what Bob [said] — if they’ll have me, I’ll ride this f-er as far as it’ll take me.’ So, to me, it’s like, ‘We just keep going, and we keep recreating with new characters.’ But yeah, that inspired me. So, thanks, Bob Newhart, for sending that to me.”

Mark Harmon on 'NCIS: Origins' Return, Why His Son Isn't Playing Young Gibbs

Fun fact: Younger versions of both Newhart’s character and Ducky appeared in the most recent season of the prequel Origins, played by Thomas Crawford and Adam Campbell (who has also guest-starred on NCIS), respectively.

NCIS, Season 24, Fall 2026, Tuesdays, 8/7c, CBS