If I go to Google image search and put in “cartoon king”, there appear to be a mix of blonde, black, red and white haired kings. Red doesn’t appear to be over-represented here. What cartoons are you thinking about?

The cartoons I’ve seen that always had a fat, red-haired king character were very obviously making reference to Henry VIII, who was a king, he was fat, had red hair, and did some silly things.

Do they? Most cartoon kings I can think of have either white or gray hair.

I have never made that sort of connection. Fictional kings? IRL kings? Sacramento Kings?Can you give some examples?

The most well-known British King, Henry VIII, was a large bulky man with a bushy red beard, dressed exactly as you imagine a King would be.

I imagine he’s something of a blueprint for the appearances of fictional kings.