I always thought that Bosom Buddies was what made him a star, and it predates every other mention of him so far in this thread (Family Ties, Mazes & Monsters, and even Happy Days [Again]). Did nobody else watch that show?
If anyone remembers him from The Love Boat I’d be impressed.
As for the rest of the quote: By the time Parenthood came out (same year as Bill & Ted), Keanu had already made at least a critical name for himself in River’s Edge.
To me, Michelle Trachtenberg will always be Nona from The Adventures of Pete and Pete.
Her dad was Iggy Pop!
Edit: And until I looked her up on imdb just now, I would have sworn she was a lot younger than she is…she’s 23! I would have thought 20 or 21.
I don’t remember that at all, but thanks for the link - it made me laugh. 
Does Giles being in those coffee adverts count? I don’t know how famous they actually made him, but I LOVED those adverts and instantly recognised him once I saw the first ep of Buffy. I think it was one of the reasons I kept on watching.
I also remember the Matt LeBlanc Heinz advert.
Juliette Lewis had a bit part in My Stepmother is an Alien. I recognised her later from it. Willow and Oz from Buffy were there too (and I recognised them both), but that’s too easy.
Speaking of Buffy: I got cajoled into watching Prison Break, and the pictures reminded me of someone. I knew it was something to do with swimming. Yup, Wentworth Miller, when in BtVS, got turned into a fish-man. He hadn’t changed at all, apart from the lack of scales. Even the haircut was the same.
If we’re using real life stuff (people we met before they were famous), that widens the field probably a bit too much. Another thread.
Remember a character named Frankie who appeared briefly during the second season of “Benson” in 1980 and 81? He was played by a young New York comedian named Jerry Seinfeld.
I remember mine. No one who saw the first couple of episodes of Shortland St could ever forget them - they were that bad! I didn’t start watching again till four years ago.
& I remember Jodie Foster from the Coppertone ads. They were really cute!
I remember mine (apart from the Keira Knightly reference). I also remember Jim Carrey from The Duck Factory, Earth Girls Are Easy (although I don’t remember him having any lines) and The Dead Pool. And of course In Living Color (with Jamie Foxx and about a billion Wayanses), although I always thought Kelly Coffield was funnier.
One of John Larroquette’s pre-Night Court roles was that of the Klingon Lieutenant Maltz (“You said you were going to kill me.” “I lied.”) in Star Trek III: The Search For Spock, although it wasn’t his first appearance. Larroquette first played Captain Stillman in Stripes.
I remember my previous one - perfectly. I made the Jim Carrey connection when I first saw Earth Girls are Easy. Just going by my own age, I probably saw Once Bitten around the late 80’s and I know I didn’t see Earth Girls are Easy until after that. I saw them both before Ace Ventura (which I saw in the theater) and I was very disappointed in AV when it came out. I thought Jim Carrey was much funnier in Once Bitten.
Kate Mulgrew to me will always be associated with Remo Williams. I saw that around '88 or '89 and even then I was amazed with how beautiful she was (and her voice kinda sticks with you). When I started watching Voyager in the late 90’s, I immediately made the connection.
And, my last one, I was babysitting and was watching All That the day that Amanda Bynes was introduced. She stuck with me because she actually made me laugh (which was a first for that show).
And, I know the roll didn’t make him famous but the first time I saw Tomb Raider, I said (aloud, in the theater), “Holy Shit! It’s Rimmer!!!”
I remember watching “Friends” and seeing Courtney Cox and thinking “Hey that’s the girl from the Bruce Springsteen video!”
Not relevant but I remember saying “OHHHHHH look it’s Rambo!” when spotting Sylvester Stallone playing a VERY small part in an old Jack Lemmon film. In the credits he was something like “man in park”.
I know I remember seeing William Shatner in the Twilight Zone episode with the gemlin. That thing haunted me for years whenever I had to travel anywhere on a rainy night.
I remember when Anderson Cooper was a news caster for ABC’s overnight news. Like, 3 in the morning, broadcasting out of London, England.
John DeLancie as Eugene Bradford on Days of Our Lives was totally unforgetable, long before he became a Q.
Not that you can say you “recognize” her but she was the baby in Lynch’s Dune too.
He became front man for the hardcore punk band Dr. Know, then in 2003 he replaced Jello Biafra in the short lived reunion of the Dead Kennedys. Then he reformed Dr. Know and toured with them again.
I looked but didn’t see this one.
I remember Gary Coleman as spoiled, semi-precocious brat on The Jeffersons, before he went on to [del]bigger[/del] more well known and better things with Different Strokes.
How about David Caruso in “First Blood?”
Erika Eleniak as the girl Elliott kisses in “E.T.”?
Not the baby, but the little girl.
And I actually did recognize her from that, when she started showing up in stuff as a teen. Not to say “Oh, it’s Paul’s little sister!” but to say, “I know I’ve seen her somewhere before.” And then, the next time I saw Dune, “Ah ha!”
I also remember Bradley Whitford (West Wing) in his sophomore year college stage production of One Flew of the Cuckoo’s Nest. Of course, we were fellow students at the time but I do remember him and remember thinking, “This actor’s going to make it big.”
I also remember Lisa Gay Hamilton (The Practice, True Crime) in stage productions of Baal and City on the Make; then again, I was a founding member of the company that staged them, so I guess that one doesn’t count.
Bill Maher will always be the wisecracking adventurer in Cannibal Women in the Avacado Jungle of Death.
The earliest thing I remember seeing Kevin Bacon in was Guiding Light as an alcoholic teen.
On a side note, Guiding Light, which will be cancelled this fall, has helped launch quite a number of acting careers in it’s 72 year run–including James Earl Jones, Billy Dee Williams, Mira Sorvino, Christopher Walken, and Hayden Panettierre.