Miles O'Brien?

[Shamrock Holmes]

Interestingly, I'm pretty sure the recurring character with the second most episodes was the conn officer Ensign Gates, whose actress was never credited and whose one line, I'm pretty sure, was spoken off-screen.

Nope, in fact O'Brien isn't even the most including only TNG (and if we include DS9, Worf beats him 283+ to 231), that's Guy Vardaman as Darien Wallace (66 episodes), who initially appeared as a Crewman, eventually reaching the rank of Lieutenant (not counting Guy's doubling Brent Spiner as LCDR Data). Ensign (late LT) Jae (aka Gretchen Naylor?) is close behind on 62 and Carl David Burks is notable as the only frequently recurring character to jump to another show in the same capacity as he added 7 episodes of VOY to his TNG tally.

 

[Shamrock Holmes]

Nope, in fact O'Brien isn't even the most including only TNG (and if we include DS9, Worf beats him 283+ to 231), that's Guy Vardaman as Darien Wallace (66 episodes),

Double-checked another source because Michael Braveheart wasn't listed on the relevant DITL page and he does have more appearances than Vardaman.

 

[Mojochi]

Dang ... I never realized that. That's impressive ... not only is he approaching Ayala territory, I didn't even think there were enough episodes with Sickbay scenes for a medical staffer to rack up that many appearances.

(And Ogawa is only in 16!)

Well, to be fair, Ogawa was a speaking role. In fact, she graduated eventually into being a regular like O'Brien, quite a lot by seasons 6 & 7, where Miles only had 3 appearances. I kind of feel like she might've been moved up to fill in where he'd been absent.

OTOH, Martinez spent the vast majority of his time on camera never saying anything, which pays differently. Dude never even got a first name. Hell, even Tess Allenby got a first name, though I can't recall when that ever came up in her 3 appearances lol

 

[CaptChris42]

And being called lieutenant by Riker in one episode.
There’s plenty of explanations of course.

Yes, the explanation I usually favour is that Captain Maxwell brevet promoted O'Brien after he lost his tactical officer on the USS Rutledge, and picked O'Brien in replacement. O'Brien went along with it for a while, but eventually argued for a return to the enlisted ranks, sometime under Picard. Perhaps to be more 'one of the boys'? Or to possibly avoid more hazardous duties (once dating Keiko?)

 

[Mojochi]

Yes, the explanation I usually favour is that Captain Maxwell brevet promoted O'Brien after he lost his tactical officer on the USS Rutledge, and picked O'Brien in replacement. O'Brien went along with it for a while, but eventually argued for a return to the enlisted ranks, sometime under Picard. Perhaps to be more 'one of the boys'? Or to possibly avoid more hazardous duties (once dating Keiko?)

OR, as I like to think of it, he'd held that rank under Maxwell during a time of war, which means it comes with a duty to very likely order others to their deaths. Maybe he just decided he wasn't going to let himself be in that role ever again. I know it would get to me.

 

[CaptChris42]

OR, as I like to think of it, he'd held that rank under Maxwell during a time of war, which means it comes with a duty to very likely order others to their deaths. Maybe he just decided he wasn't going to let himself be in that role ever again. I know it would get to me.

Yeah, that also makes a lot of sense to me. And something I'll bare in mind, if I ever get this O'Brien/Cardassian War fanfiction off the ground (at long last) too...

 

[NigellaDeanna20]

That WAS Colm Meany and yes i believe that was O'Brien he just hadn't been given his first name yet. Don't forget he was an unnamed conn officer in EAF and was a semi-cast member at that point before he became an official supproting character.