[proud American in Canada]

Since you said “comic actor,” the answer is Buster Keaton, with Charles Chaplin a close second.

After movies became talkies, the spoken joke became as important as the acted joke, and comedians shifted accordingly. The top three would be, in no particular order, Groucho Marx, Robin Williams, and Steve Martin.

What you said, though I would also add, as many others have said, Jackie Gleason.

But Robin could do comedy and serious movies as well. As can Steve Martin.

And that is amazing what a talented musician Mr. Martin is. I suppose artistic impulses find a way to be expressed, if the person has the energy and will to work.

[chajin]

As did Gleason. His portrayal of Minnesota Fats in The Hustler is still, I think, the go-to for that archetype.