CBS put out the first-look photographs on 1 September. Mark Harmon, in Alaska, with a rescue dog, as Leroy Jethro Gibbs — a role he walked away from on 11 October 2021 after eighteen years, with the line "I'm not going back, Tim. I'm not going back home."
He is going back. Season 3 of NCIS: Origins premieres Tuesday 6 October at 10/9c with an episode titled "Don't You Forget About Me," and Harmon appears in all ten episodes as part of a season-long present-day mystery. This is not a cameo. It is a co-lead. (For everything else landing this month, see our full September guide with episode counts and drop patterns.)
The show's best night was the night it stopped being a prequel
For two seasons the format was odd and slightly melancholy: a series about young Gibbs in 1991, narrated by the actor who used to play him, describing a man someone else was performing. Then came the Veterans Day crossover on 11 November 2025 — NCIS's "Now and Then" and Origins' "Funny How Time Slips Away" — and Harmon stepped in front of the camera for one hour, alongside Muse Watson returning as an older Mike Franks.
The result was the highest-rated episode the show has ever aired:
- Crossover, 11 November 2025: 5.576 million viewers, 0.491 in the demo — a series high.
- Season 2 average: 4.15 million viewers, 0.24 demo.
- Season 1 average: 3.88 million, 0.27 demo.
- Season 2 versus Season 1: viewers up 7%, demo down 11%.
- Series premiere, 14 October 2024: roughly 5.0 million across a double episode.
CBS drew the obvious conclusion, and it is hard to argue with. Also worth noting: the episode that brought Gibbs back aired on Veterans Day, on a show about naval criminal investigators. Twenty-three years in, the franchise has not lost its touch for scheduling.
More Harmon, less show, announced in the same breath
Seasons 1 and 2 ran eighteen episodes each. Season 3 runs ten — a 44% cut, decided in the same upfront cycle that also trimmed NCIS: Sydney to ten and handed it the Tuesday 10pm slot at midseason. The season in which the franchise's biggest star finally returns full-time is the shortest the show has ever had.
Meanwhile the empire keeps widening. NCIS: New York was ordered to series on 15 April 2026 — the franchise's seventh show — with LL Cool J bringing Sam Hanna over from NCIS: LA, alongside Scott Caan and Jennifer Beals. On 6 October, CBS airs three straight hours of it: NCIS Season 24 at 8, NCIS: New York's premiere at 9, Origins at 10.
The reunion nobody could kill
Here is the sequence, and it is close to comic. NCIS: Tony & Ziva premiered on Paramount+ on 4 September 2025. It scored 82% on Rotten Tomatoes, debuted at No. 8 on Nielsen's streaming chart with 371 million viewing minutes, and was cancelled on 19 December 2025 after one season of ten episodes.
The stated problem: 80% of its audience was over 50. On a subscription streamer chasing growth, that is a death sentence. On broadcast television, it is a business model.
So on 6 October, Michael Weatherly walks back in as Tony DiNozzo — a recurring, season-long arc on NCIS Season 24, opening the premiere by setting up a Washington satellite office for his private security firm — in the hour immediately before Mark Harmon walks back in at 10pm. Two "final" exits, both undone on the same night, on the older platform, for the older audience.
Two eighteen-year runs, passing in opposite directions
Rocky Carroll played Director Leon Vance from Season 5 and left as a series regular at the end of Season 23 in May 2026. Eighteen years — exactly the length of Harmon's own run as a regular. The season one NCIS veteran of eighteen years steps out is the season the other steps back in.
And the show he is stepping into is not the flagship but the prequel about his younger self, where Austin Stowell plays Gibbs in 1992 and Harmon plays Gibbs in the present, in the same episode, working the same case. A franchise that began as a backdoor pilot inside JAG in April 2003 has now accumulated enough history to make its own lead actor his own guest star.
What the showrunner says
David J. North, now sole showrunner after co-creator Gina Lucita Monreal's exit at the end of Season 2, on why Harmon agreed:
"It had been almost six years, and we both really loved the idea that he had settled in Alaska, that he was happy, that he had this new rescue dog. But at the same time, Mark was excited to give the fans what they wanted."
"When we first see Gibbs in the season premiere, he is still in Alaska with his trusted rescue dog but soon finds that the peace he found there isn't going to be easy to hold on to. Ghosts from his past are catching up to him, and it may be enough to pull him out of retirement."
Harmon's own account of how he was talked into the crossover, to TV Insider, remains the most Gibbs answer available: "I just trust them. This is their show." He said much the same on the Origins set in 2024 — "I'm there to help and to talk to them or to tell them what I remember from being in this for a while. But this is their thing."
What nobody has said
- Whether Season 3 is the last. There is no Season 4 renewal, and a ten-episode order plus a slot handed to NCIS: Sydney at midseason is the shape of a wind-down.
- Whether Harmon appears beyond it. He was explicitly noncommittal in November 2025.
- Whether the present-day mystery connects to NCIS Season 24 or NCIS: New York.
- Whether the Tony & Ziva storyline is ever resolved. Weatherly's return reportedly does not retcon it, which is not the same as continuing it.
- Any Season 3 guest casting at all. The only official information comes from the CBS releases of 30 June and 1 September — be sceptical of anything else.
One number to keep in perspective: every rating above is live plus same day. No Live+7 or multiplatform figure has ever been published for Origins. If you see one, it did not come from CBS.