Actor Adam Campbell is bringing Dr. Donald “Ducky” Mallard back to NCIS: ORIGINS on Oct. 20, giving young Leroy Jethro Gibbs another chance to work alongside a friend viewers already know he will treasure.
“Let’s just say he comes into a case this year in a way that he hasn’t in his previous two episodes…he sort of just ends up popping up,” NCIS: ORIGINS showrunner David J. North teased when he confirmed Campbell’s Season 3 return in August.
Now, CBS has revealed the case that brings Ducky into the story. In 1992, a young Marine turns up murdered on a beach, with suspicious markings covering his body. Ducky helps the team investigate in the episode “Return of the Mack,” which airs Tuesday, Oct. 20, at 10 p.m. ET/PT.
That puts Campbell’s medical examiner back in the same story as actor Austin Stowell’s younger Gibbs. Actor Mark Harmon also appears as the present-day Gibbs, giving the series two very different points in one man’s life to explore.
The appeal goes beyond recognizing a familiar face. On NCIS, Harmon’s Gibbs and the late actor David McCallum’s Ducky shared a bond that felt lived-in; the prequel has the opportunity to show how that trust took shape before viewers met them on the original series.
North told TVLine that Ducky’s Season 3 presence would help explore the beginnings of that close relationship. He also confirmed Campbell’s return as a recurring character, giving the show room to develop that connection.
Related: Here’s What You Can Expect from NCIS: ORIGINS Season 3
Campbell already knows his way around the role. Before joining the prequel, he played the younger version of McCallum’s character in NCIS flashbacks, giving the franchise a familiar performer to carry Ducky into another chapter.
His first NCIS: ORIGINS appearance, in Season 2’s “The Edge,” carried particular meaning. Deadline reported that the episode honored McCallum, even featuring the actor’s music, while sending Ducky to Camp Pendleton to shadow the team and reconnect with Gibbs.
That visit did not begin with everyone instantly embracing him. As TVLine recapped, Ducky arrived to assess whether the office needed its own medical examiner, and the team initially questioned his presence before warming to him.
He eventually offered more than professional expertise. He helped fellow team members through personal difficulties and gave Gibbs a ship in a bottle. That small gift nudged Gibbs back toward boat-building, connecting a new friendship to a pastime longtime viewers associate with the character.
Campbell returned later in Season 2 for “Homeward Bound,” which aired March 31, 2026. When authorities arrested medical examiner Dr. Tango, played by actor Julian Black Antelope, for stealing human remains from a national park, Ducky helped the team try to prove his innocence.
Those visits give the October reunion some history of its own. Rather than introducing Gibbs to a stranger, the series brings back someone who has already offered him friendship and shown up when another colleague needed help.
CBS also promises a present-day reunion for Harmon’s Gibbs in “Return of the Mack.” But for viewers especially fond of Ducky, the 1992 investigation offers its own reason to tune in: another piece of the friendship that helped give NCIS its heart.
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