There is no evidence in Lewis Carroll's books to suggest that the Hatter is an alien, so the answer is no.
(Of course, maybe the Hatter knows something that Lewis Carroll doesn't) ;)
No, the Mad Hatter is a human being.
Johnny Depp plays the Mad Hatter in the new Alice in Wonderland movie.
In Alice in Wonderland, the Hatter is never seen without a tea cup.
Alice in Wonderland
In "Alice in Wonderland," the Mad Hatter does the Futterwacken dance during the song "Alice's Theme."
mad hatter
The Hatter is a character in Lewis Carroll's book, Alice's Adventures in Wonderland. In the 1951 Disney animation, he is called the Mad Hatter.
The Hatter asked Alice the famous riddle, "why is a raven like a writing desk?"
Johnny Depp played the Mad Hatter.
No
In Tim Burton's Alice in Wonderland, the Mad Hatter.
Johnny Depp played the Mad Hatter.