NCIS 500th episode guest stars: every cameo in "All Good Things"

Rather than packing "All Good Things" (season 23, episode 13) with nostalgic walk-ons, the show gave every guest star an actual role in the story.

The guest stars

• Adam Campbell as Young Ducky Mallard — the episode's biggest surprise. Campbell has played the younger version of Dr. Donald "Ducky" Mallard (originally David McCallum, who passed away in 2023) in flashback episodes over the years. This time, he appeared as a spirit guiding Director Vance into the afterlife — the first time he's played Ducky as a ghost.
• Adhir Kalyan as the mysterious interrogator — known from United States of Al and Rules of Engagement. Spent most of the episode grilling Vance about a case. The twist: he was Young Ducky all along, easing Vance into the realisation that he hadn't survived.
• Matt Cook as CID Agent Dolan Thompson — from Man with a Plan. The corrupt Army CID agent who ultimately shoots Vance. Starts out as a seemingly harmless colleague. Doesn't stay that way.
• Austin Marques as Billy Fuentes — son of a Marine Gibbs helped in a Season 1 case. His sister's framing for murder is the thread that reunites the disbanded NCIS team.

What about the classic cast?

No Mark Harmon, no Michael Weatherly, no Cote de Pablo. None of the big legacy names appeared in person.

The episode was packed with nods to them, though:

• Kasie found Abby Sciuto's old clothes in storage, including her iconic platform boots
• A background sign referenced Naktok Bay, Alaska — where Gibbs settled after leaving
• A career-spanning montage of Vance's finest moments doubled as the farewell reel

Separately: Emily Wickersham returned as Eleanor Bishop earlier in season 23, but in episodes before the 500th — not in this one. Her comeback came with a twist: Bishop is now classified as a cyberterrorist.