Fallon plays LT Rice in little more than a cameo. Rice belonged to one of the fleeing units from the Battle of the Bulge. While everyone else was running away he knew the 101st would need ammo so he raided his units ammo dump and brought them as much as he could. It’s a true account of what happened but Fallon is Fallon and it took me right out of the episode. Same for Simon Pegg but I didn’t know him when he was cast in his very small role.
Yep it’s Robin.
Thanks. When I first saw B of B, Jimmy Fallon was not on my radar and I haven’t re-watched in a while. When I do watch, I always commit to the whole series, in chronological order, so it’s not that frequent.
Couldn’t find him in the IMDB for the series.
Jerry Mathers = the Beaver
Every time I see Adewale Akinnuoye-Agbaje on-screen I’m all “Look! It’s Adebisi!” Every. Time.
Bryan Cranston will always be Heisenberg to me. Not Hal from Malcolm in the Middle, nor Walter White. Heisenberg. He will turn to evil everything he touches.
At the time he was on Saturday Night Live so he was pretty famous. There were a few others that stand out now that were unknown then.
Simon Pegg: played Easy Co First Sergeant. His glider was shot down on D-Day. He had one or two lines. This was post-Spaced/ pre-Shaun so British audiences would recognize him but not American.
Jason O’Mara: Terra Nova, Vegas, Life on Mars played the first Easy Co commander.
Michael Fassbender pre-movie star
Jamie Bamber pre-Battlestar
Tom Hardy before he was Bane
Mark Shephard will always be Badger from Firefly despite the fact that I’ve since seen him in about 6 other shows.
Tobolowsky will always be Ned Ryerson from Groundhog Day for me.
I absolutely agree with you about Wes Studi. He should’ve gotten at least two or three Oscars for Last of the Mohicans - wow, what a scary character, and perfectly played! He’s funny in Mystery Men, though.
My mom is an avid watcher of The Young & the Restless and General Hospital and just recently her favorite GH actor went to Y&R which is very crushing to her because she can’t stop looking at him as his GH character. Are there any fans of Steve Burton as General Hospital’s Jason Morgan here?
If so, God bless you and him and my mom always!!! 
Holly
Sarah Michelle Gellar shall always be Buffy Summers.
I can’t believe no one has mentioned Peter O’Toole yet. What an unlucky break for an actor, to have his very first starring role be the defining one of his career. But no matter what else he’s done, people always think of him playing Lawrence of Arabia, and there’s no changing that.
Shooter McGavin. He’s been in tons of stuff I have no idea what his real name is. Nor do I care to know. He was so perfect as Shooter I will never associate him with anything else.
Also, the kid who played Spiderman in the latest version is forever Eduardo Saverin to me. I don’t know his real name, either.
See also: Christopher Reeve.
That’s what I’m talkin’ about. I guess because I had 1776 so firmly in my brain first, when KITT and Dr. Craig came along, I was just stuck on John Adams. (As CalMeacham notes, he was also John Quincy Adams in the Adams Chronicles miniseries, but the 1776 role was far more memorable.)
A few more:
Ed Asner–Lou Grant
Penny Marshal–Laverne De Fazio
Chevy Chase–host of Weekend Update (no NOT Clark Griswold)
Trying to stick to ones I haven’t seen others say yet.
Kathy Bates is always Annie Wilkes from Misery. Like even in something as silly as Waterboy, she was still creepy as all hell.
R. Lee Ermey is Gunnery Sergeant Hartman from Full Metal Jacket. Hell, he has to be one of the most type cast actors out there, no?
I have met and spoken to William Daniels many times.
I swear every time he would start to talk I wanted to look around for a black car.
David Boreanaz will always be Angel. As much as I like him on Bones, I keep expecting him to go all vampire on a perp.
Every time I see David Tennant / Christopher Eccleston / Matt Smith in anything, I’m seeing Doctor Who. That goes for Billie Piper / Freema Agyeman / Catherine Tate as well - Rose Tyler the hooker, Martha Jones the lawyer, Donna Noble the paper saleswoman, etc.
To every Trekker, Christopher McDonald will always be the doomed Lt. Castillo: Richard Castillo | Memory Alpha | Fandom