When you think of NCIS royalty, names like Mark Harmon, Michael Weatherly, or Pauley Perrette probably pop into your head, right? They’re practically synonymous with the show. But plot twist—it’s none of them who hold the crown for the most episodes under their belt. Yep, one actor stealthily outran them all, clocking in a record-breaking number of appearances without most fans even realizing it.
This isn’t about Gibbs’ stern leadership, DiNozzo’s cheeky one-liners, or Abby’s gothic charm. Nope, this champ played the long game, sticking around like a shadow in the background while fan favorites came and went. Think you know who it is? Spoiler alert: you’re probably dead wrong, and the truth might just blow your mind.
David McCallum’s Legendary Run: How NCIS’s Ducky Quietly Became the Show’s Ultimate Episode King
NCIS smashed records with 22 seasons, becoming CBS’ longest-running show. But here’s a twist: the actor with the most episodes isn’t Mark Harmon (435), Michael Weatherly (308), Pauley Perrette (354), or Sean Murray (437). It’s David McCallum, the OG medical examiner Donald “Ducky” Mallard, who’s clocked an insane 452 episodes.
McCallum’s Ducky takes the crown, proving that being the quirkiest guy in the morgue has serious staying power. For McCallum, it’s been one crazy ride. His all-time favorite moment, though? Scoring the role. He asserted,
After auditioning for both Paramount and CBS the call from my agent telling me that I got the part of ‘Ducky’ is my favorite moment.
Since then? Hundreds more. But it hasn’t all been smooth sailing. At one point, McCallum thought it might be time to hang up the lab coat, feeling like Ducky’s story had hit a dead end. Instead of writing him out, the showrunners offered a scaled-back role, letting him stay in the mix without overdoing it. Smart move.
Now, with NCIS still going strong, David McCallum’s record is untouched.
Mark Harmon Turned Down an NCIS Tell-All and Delivered a Real Spy Story Instead
Mark Harmon, the face of NCIS for nearly two decades, had no plans to pen a tell-all about the hit series after his exit. When Harper Select pitched the idea of a book tied to the show, Harmon flat-out declined. Instead, he turned his focus to Ghosts of Honolulu, co-written with Leon Carroll Jr., a former real-life NCIS agent.
Harmon wanted to honor the real NCIS—cases that inspired the show’s roots. The book tells the story of Douglas Wada, the first Japanese American in Central Intelligence, set against the backdrop of Pearl Harbor. For Harmon, it wasn’t about murder mysteries but authenticity and history.
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