Mark Lenard is the first. Who is the second actor to play three different aliens in Star Trek?

Answer 1

Someone look into J.G. Hertzler (I think his name is), who, as far as I remember, played a prominent Klingon on DS9 (Martok?). I'm sure he's played more than two characters.

RESPONSE: Actor J. G. Hertzler (the J. G. stands for John Garman) did indeed act out a prominent Klingon, and that Klingon's name WAS Martok. And he DID act out more than two characters; the first was the unnamed Vulcan captain of the Saratoga(he was credited as Garman Hertzler then), and the second was a human artist named Roy Rittenhouse.

Another one to look into would be the actor who plays Shran in Enterprise, Jeffrey Combs. He'd played Shran and an idiot Ferengi in Enterprise. Oh, and of course his role in DS9.

RESPONSE: Mr. Combs acted out TWO roles there; the one was the Ferenginarian Brunt and the other was the Vorta operative Weyoun--including all his clones. The actor David Warner appeared in Star Trek motion picture 5 as a disgraced human ambassador, in motion picture 6 as the Klingon Chancellor who is assassinated, and as the Cardassian who tortures Picard over the number of lights.

COROLLARY: Mr. Warner's role AS that Cardassian, a "gul" by the name of Madred, was one he acted out in "Chain Of Command, Parts I And II Of Two."

ADDENDUM: Actor James Horan may hold the current record for most distinct roles in Star Trek series programs. He acted out the evil Takaran scientist Jo'Bril in "Suspicions," the Jem'Hadar Ikat'ika in "By Inferno's Light," the Kolaati criminal Tosin in "Fair Trade," and--and this last was probably the only sympathetic character he was ever known to have acted out--the human Support Services Section Lieutenant Albert Barnaby in "Descent, Part II Of Two."