Which actor has appeared in the most NCIS episodes?

To call NCIS a long-running franchise would be an understatement. It crossed the coveted 1,000 episode mark earlier this year, and has been around for over two decades. That's a lot of screen time for its various characters. Only a few of them however, can lay claim to being around for most of NCIS' history.

There are only seven actors who have crossed the coveted 300 episode mark. The next closest is Cote de Pablo, who has appeared in 173 episodes (though she will get to add to her total with the upcoming Tony and Ziva spinoff).

Mark Harmon has the third-highest episode count

The 7-4 spots on the most NCIS appearances list look like this:

7. Michael Weatherly (310 episodes)

6. Pauley Perette (355 episodes)

5. Rocky Carroll (359 episodes)

4. Brian Dietzen (368 episodes)

The usual suspects as far as long-tenured actors go. Dietzen is still adding to his grand total, so he could eventually crack the 400 episode mark that only three actors have managed to hit. That being said, it's going to be a while before he surpasses Mark Harmon, who currently sits at 437 episodes.

Sean Murray will break the NCIS record in 2025

Harmon is unlikely to make a return to NCIS anytime soon, but he will provide narration for the upcoming spinoff NCIS: Origins, so it remains to be seen whether those will count (let's say, for the sake of argument, they don't). The most interesting development, however, is between the top two spots on the list.

Sean Murray currently has 452 episodes under his belt, while the top spot goes to David McCallum with 459 episodes. The thing is, McCallum passed away before the events of last season, and Murray is still very much a part of the show.

Barring some major casting shakeups, Murray will be able to surpass McCallum and become the actor with the most NCIS appearances of all time. Given the discrepancy between him and the rest of his peers, it's hard to imagine anybody challenging him.