Actors in more than one recurring role in a series

[Jokerz79]

Armin Shimmerman was working at the same time as Principal Skinner on Buffy, and as Quark on Deep Space 9, which sounds like a lot of work! (And, IIRC, both shows ended at the same time, so he went from double-booked to looking-for-work-actor in the same year!)

But pretty much any episode where a character has to fight an imposter of themself seems to loosely fit the OP. In Agents of SHIELD, Melinda May had to fight an enemy agent who used some sort of face-distorting mask to appear to be her, and it was pretty much May vs. her stunt-double for all their fight scenes, switching her clothes back and forth as the actress is whichever of the two characters is speaking at the time (while the stunt-double has her back to the camera). The agent-pretending-to-be-May was in a half-dozen or so episodes that season, but I'm not sure if she would really count as 'recurring.' (Certainly Xander's double, from an episode of Buffy where he got split in two, or Kirk's 'transporter clone' or Mirror Universe self, from old Star Trek episodes, don't count, but maybe Tom Ryker, who appeared more than once, does? Or maybe not, since, IIRC, his first appearance was in Next Generation, and his second was in Deep Space 9...)

While doing those two roles he would also pop up as a judge in the Practice a character carried over to the spin off Boston Legal where he had scenes with Rene from DS9 playing a lawyer at Denny Crane's (Bill Shatner) firm.

[AnakinFlair]

That principal was killed off at the end of season 4 or 5, so Shimerman was only working on DS9 for the next two years or so.

Killed off at the end of Season 3, actually.

I just found out David Ramsey, while a regular on Arrow, also had a recurring guest role on Blue Bloods.

Someone mentioned Tom Cavanaugh played multiple versions of Wells. There was a scene during Crisis on Earth X where he played both Harry Wells and Eobard Thawne in the same scene. Also during that crossover, Stephen Amell played the Earth 1 and Earth X version of Oliver Queen. And Melissa Benoist also played the Earth 1 and Earth X versions of the character in the same scenes at the same time.

Katie Cassidy played three versions of Dinah Laurel Lance throughout both Arrow and The Flash- Earth 1 Laurel, Earth 2 Laurel, and Earth X Laurel.

[j9ac9k]

I'm a little surprised we've never had a supporting character on a show concurrently also star in their own spin-off at the same time - have we? (like, imagine if Frazier's job was in Boston but so he'd go to Cheers after work to hang out and there wouldn't be much spill-over aside from the occasional comment that hinted at things that were happening on his spin-off) The aforementioned Oscar Goldman might be the closest to that.

On the other topic, I remember Heather Locklear doing double-duty on "Dynasty" and "TJ Hooker" at the same time. D'Arcy Carden was also on "The Good Place" and "Barry" at the same time. (as was Kirby Howell-Baptiste, in smaller roles)

[Jokerz79]

I'm a little surprised we've never had a supporting character on a show concurrently also star in their own spin-off at the same time - have we? (like, imagine if Frazier's job was in Boston but so he'd go to Cheers after work to hang out and there wouldn't be much spill-over aside from the occasional comment that hinted at things that were happening on his spin-off) The aforementioned Oscar Goldman might be the closest to that.

On the other topic, I remember Heather Locklear doing double-duty on "Dynasty" and "TJ Hooker" at the same time. D'Arcy Carden was also on "The Good Place" and "Barry" at the same time. (as was Kirby Howell-Baptiste, in smaller roles)

Empty Nest and Golden Girls would have cameos due to them being neighbors with Sophia joining the Empty Nest cast after Golden Girls and Golden Palace ended.