Oh yes, Leonard Nimoy plays an Indian outlaw in “The Maggie Hamilton Story”
His character’s name is Fallen Eagle, Falling Eagle, or Logical Eagle. Something like that…
Fascinating.
Elisha Cook, Jr, Kirk’s Lawyer Samuel T. Cogley in “Court Martial”, as well as the gunsel in the Bogart film, “The Maltese Falcon” played “Snooker”, reformed crook, Salvation Army singer and reluctant assassin in the “Pter Gunn” episode, “The Long, Long Ride”.
Sherry Jackson, Andrea in “What are Little Girls Made Of” in the Rawhide episode “A Moment in the Sun”.
Sounds like something definitely worth watching! 
Jane “Amanda” Wyatt as “Lois Frazer” in the 1950 noir The Man Who Cheated Himself.
Last night I watched the Oscar-winning (but to me underwhelming) British film Chariots of Fire, which had three people in the cast with later ST appearances. The first two played sweethearts in the movie.
Similarly, Phoebe’s in-laws in a Friends episode I just saw were played by an actor and actress with ST in their futures.
Nice article on Shatner at just a decade shy of a hundred:
After finding the first Voyager episode on youtube, I flipped the usual premise of this thread, and cheated by researching instead of spotting on television.
I wondered about Scott Jaeck, playing the rather obscure Lt. Cmdr. Cavit, second in command, who lived and died in the first episode. He has a long career from the mid-80s to present, including an episode on T. J. Hooker, and as “Administrator” on ST:TNG The Inner Light (where Picard spends 25 minutes living 40 years on a doomed planet). Most parts were one-off, though a couple he managed 4 or 5 episodes. One show was Newhart, playing Marv Stribling. Marv’s claim to fame was walking from Vermont to California.
By the way, I don’t know if this counts for spotting, but the title of the episode The Inner Light came from George Harrison’s song of the same name, the lyrics coming from Tao Te Ching, written by Lao Tzu / Laozi.
Heck yes that counts!
Meg Wyllie, the Talosian Keeper in the first Star Trek: The Original Series (1966) pilot “The Cage”, played a nutso maid with an Irish accent in the Peter Gunn episode, “A Slight Case of Murder”. She worked for Mr. Barnaby, played by Howard Terbell McNear, Floyd the barber of Mayberry fame, who as a member of a grand jury where none of the indited gangsters went to trial, is blowing them up by various explosives.
Been watching (on YouTube) episodes of Kraft Suspense Theater. Every one seems to have at least one Trek actor in it. “The Name of the Game” has four. Grace Lee Whitney (Yeoman Rand), Barry Atwater (Surek), Steve Ihnat (Garth), and Nancy Kovack (Nona).
George “Sulu” Takei and John “Kor” Colicos in the Hawaii Five-O episode “Death’s Name Is Sam” (1975).
Robert Picardo is also in Amazon Women On The Moon as the funeral director.
^ Look at all that hair!
This episode was especially interesting because Takei was an undercover cop trying to get away from the bad guys by stealing their helicopter. Colicos blew him out of the sky (so to speak) with a surface-to-air missile (SAM), hence the title.
That’s ridiculous. No one can shoot down Sulu!
Takei was also in the re-boot Hawaii 5-0 as one of Chin Ho Kelly’s “uncles”; a moonshiner.
“Revenge is a dish best served cold.” —Klingon proverb
If DS9 can have Friends-style opening credits (see above), no reason VGR can’t, too:
Did a full cast check on that one. It also had William Marshall, Ed Begley Jr., Bernie Casey, Ronnie Cox and Dick Miller. So TOS, Voy, DS9, and TNG are all covered.