Fishburne appeared in Apocalypse Now in 1979 as Clean, one of the men on the boat that bring Martin Sheen up the river. He lied about his age to get the part.
The racist major in that MAS*H episode has been in lots of things too…the first that comes to mind is Lethal Weapon.
Speaking seperately of Jeff Goldblum and Annie Hall, he was the guy at the L.A. party who has to call his guru because “I forgot my mantra”.
Also, I’ve always been fond of Harrison Ford’s bit parts in American Grafitti and Apocalypse Now.
And, I remember reruns of “Growing Pains” with Jennie Garth pre-90210 and Matthew Perry (Carol’s boyfriend who dies in drunk driving accident — a very special episode). Of course, Leonardo DiCaprio also got his start there. Makes you wonder if the kid that played Ben is selling used cars or insurance.
Blake was one of the later Little Rascals
I’m gonna have to call you on this one. While Tom Hanks wasn’t the superstar that he is today, he wasn’t exactly unknown, either. He was the star of a sitcom called Bosom Buddies which ran from 1980-1982, so he was moderately famous by the time he did Ties.
Everyone mentioned Star Trek but I didn’t see mention of Nicci Cox’s appearance as a young alien girl on TNG. Of course, whether she’s a star is debatable, but she’s pretty hot. Unhappily Ever After was actually a moderately successful show compared to the standard fare on the 5th and 6th networks.
I’m not sure whether James Earl Jones had done much by the time he had that one-line bit part on Strangelove. Allright, it’s more than one line if you count “release 1st safety”, “release 2nd safety” “radar switched to target orange”, “bomb doors negative function”, “firing explosive bolt”, and “bomb doors still negative function.” Those aren’t lines, they’re following orders. If he’d been a bigger star at that point, he probably could have persuaded them to keep his longer speech in.
Future Star Trek actors also show up a lot on Hill Street Blues. Watching the reruns on Bravo, I’ve seen Johnathan Frakes, Armin Shimerman, Tim Russ, and the guy who played the Traveler, all in small parts.
Marc Alaimo and Bablyon 5’s Peter Jurasik make regular appearances in Hill Street’s final seasons. I imagine they were well-established character actors at this point, but it always makes me happy to see them. Future Dukat and future Londo!
Mary Pickford played a party guest in her first film, Mrs. Jones Entertains (1908), one of the popular Jones series starring Florence Lawrence and John Compson—perhaps the first long-running “sitcom.”
Geena Davis also appears on Family Ties as an inept maid hired by Alex. She suffers from a terminal case of 80s Big Hair.
Watch the various Roots shows for Star Trekkers-to-be, too:
Roots
LeVar Burton
John Schuck
Roots: The Next Generation (an interesting thing in and of itself, no?)
Brock Peters
Paul Winfield
Roots: The Gift
Avery Brooks
LeVar Burton
Kate Mulgrew
Tim Russ
Some of these folks were already well-known, and none of these were really “bit” parts, but still. It’s noteworth.
Estelle Parson more than had a part in Bonnie and Clyde - she won an Academy Award for Best Supporting Actress for her role.
May not be as old, but talking about Lawrence Fishburne gave me pleasant thoughts about Cowboy Curtis on PeeWee’s Playhouse. Now THAT was some fine TV!
The movie This Is Spinal Tap reads like a virtual “who’s who” of later-to-be-famous people:
[list]
Dana Carvey and Billy Crystal play mimes at the party hosted by Bobbi Fleckman, who is played by Fran Drescher.
The Stonehenger designer is played by Angelica Houston.
Bruno Kirby is the limo driver at the beginning.
Although he was at least fairly well-known as a songwriter (he DID co-write “It’s Raining Men”) and sidekick for David Letterman, Paul Schaffer plays a disc jockey in the movie.
Here’s one I spotted back when AMC still showed old movies: in the 1956 musical cheapie Rock, Rock, Rock, there’s an audience of teens listening to Frankie Lyman and the Teenagers sing I Am Not a Juvenile Delinquent. Right up front—looking just like herself—is a 15-year-old (or so) Valerie Harper.
Joe Pesci was a drummer for Joey Dee and the Stalighters in 1961’s Hey, Let’s Twist.
BTW, Bobby Blake in Treasure of Sierra Madre was a little boy selling lottery tickets.
Valerie Perine played the buxom woman given to Kilgore Trout in the movie version of “Slaughterhouse Five.” I think she appeared in Playboy shortly thereafter.
That would be the Rev. Matthew Fordwick, and he was actually a recurring character, not just a one-shot. On the IMDb, he’s listed as having one guest appearance, then listed as a cast member from 1973-1976.
'Course not long after, he turned in his collar, fell from grace, and posed as a homosexual to move in with a couple of tramps out in California. 
Elvis’ Roustabout has an opening scene with Raquel Welch as a college gal in a tea house and Teri Garr as one of the “crowd” dancers. In fact, Terry danced in at least four more of Elvis’ films, including **Fun in Acapulco, Kissin’ Cousins, Viva Las Vegas **and Clambake.
Speaking of John Ritter, he played a minor role in the 1971 horror film The Other (not to be confused with “The Others”, heh.)
And Paul Schaffer played a PR man in Spinal Tap, not a DJ, if I recall correctly.
Speaking of Teri Garr, let’s not forget about her memorable guest appearance in that weird Star Trek episode where they go back in time and find “Gary Seven” from the future or something. I always wondered what the hell was going on in that episode - like they were going to spin off “Gary Seven” into his own TV show later on. Teri looked pretty good, though…
Yep. Exactly like that, as a matter of fact.
And people think Voyager was bad.