And don’t forget The Number 23.
Tom Hanks always seems to play some version of himself in films but really threw everyone for a loop when he became Forest Gump. Zero Tom Hanks in that character.
Huh…I always think of Forrest Gump as peak Tom Hanks.
Alison Brie hasn’t been nominated for an Oscar, let alone won.
He meant Brie Larson.
That’s because the poster meant Brie Larson. A semi-common mistake.
And he missed Rita Moreno!
Doy. I always say one when I mean the other (same with Clark Gregg and Gregg Henry).
In my defence, both Bries were on Community.
And yeah, I missed the fourth in Rita Moreno.
Came in to post about this. He was still somewhat Ferrellish but it worked as he played it straight in a weird situation.
Pacino is way out of his pigeonhole in Hunters.
Many of Pesci’s roles fall into a niche but he certainly isn’t playing himself. In real life he’s rather introverted.
Henry Fonda played a similar type in many of his movies with a few notable exceptions. (See Once Upon a Time in the West.) Mostly he was an affable Everyman. Apparently that was not him playing himself. When asked how his father was in real life Peter Fonda famously said, “Watch Fort Apache.”
To be clear, even though the phenomenon is commonly described as “actors always playing themselves”, as I remarked in my OP, that isn’t always literally true. A more precise, though more verbose, description might be “actors who always seem to be playing approximately the same character”, and that character may or may not be based on the actor personally.
The OP is confusing since Jack Nicholson is used as an example. In no way should be in the category of someone who only plays one character.

Then I saw him play the villain in Doom.
A cyberdemon?

He meant Brie Larson.
That’s a rather cheesy mistake to make.

Tom Hanks always seems to play some version of himself in films but really threw everyone for a loop when he became Forest Gump. Zero Tom Hanks in that character.
He’s the villain of Ladykillers and he is SUPER different in Cloud Atlas.
He and Michael Keaton both made the big switch from being associated as comedic actors to guys who can take serious roles. Seriously, Keaton getting Batman was party controversial because he was mostly a funny guy.

I found it depressing that the most recent F&F movie had no fewer than three Oscar winners in its cast (Helen Mirren, Charlize Theron, Alison Brie)
There are FOUR Oscar winners in that movie. You forgot Rita Moreno. (And of course it’s Brie Larson, not Alison Brie.)
Some exceptions to Jack Nicholson playing the same character were already mentioned.
But the fact he often plays some form of a Type A, aggressive, dominant, alpha male is pretty apparent to me. Whether he’s a mental patient or in the military at Guantanamo Bay.
Of course, the Oscar-nominated role that really put Nicholson on the map was, uh, a soft-spoken small-town lawyer who honestly sympathizes with the longhairs before he reluctantly lets them coach him on the finer points of recreational marijuana use? Oh, boy, he sure wishes he could tag along with the main characters…
Tom Cruise deserves a shout out for playing Les Grossman in Tropic Thunder.
I mean, he doesn’t play himself in everything. He is in Magnolia and Collateral and is totally different in those.

The OP is confusing since Jack Nicholson is used as an example. In no way should be in the category of someone who only plays one character.
Perhaps he doesn’t deserve it, but he does very often turn up in lists of such actors.