Who was the narrator of "Rip van Wrinkle" by Washington Irving?

The plot of Washington Irving's "Rip Van Winkle" is framed before and after by material that does not advance the plot. The purpose of the material which frames the plot is to create the illusion that the story is fact and not fiction.

Washington Iriving with tongue in cheek irony attests in the opening section of the frame by means of the quotation in verse:

By Woden, God of Saxons,

From whence comes Wensday, that is Wodensday,

Truth is a thing that ever I will keep

Unto thylke day in which I creep into

My sepulchre CARTWRIGHT.

and a note explaining where the story came from to the veracity of the story.Irving reiterates the claims to the truth of the story after the story has been narrated, by means of the narrator attesting to the truth of the story and by quoting from the letter of Knickerbocker stating that the story is true "beyond the possibility of doubt."

The only one who knows what Rip saw on that mountain is Rip himself. He has told the story frequently, but he is not the narrator of Rip Van Winkle. In the note at the end of the story, Knickerbocker claims to have heard the story from Rip's own mouth and Knickerbocker gives it his full belief. But it is not Knickerbocker, either, who tells the story, but a different narrator. Readers of the entire The Sketch Book of Geoffrey Crayon, Gent. know that the narrator is Geoffrey Crayon, Gent. (for gentleman), the purported author of the book. Crayon claims to have found the manuscript of Rip Van Winkle among papers left behind by Knickerbocker after his death, and Crayon appears to revere Knickerbocker for his unquestionable authority.

The frame creates, then, several layers of doubt. Crayon, of questionable judgment, has the story from the unreliable Knickerbocker (if he is telling the truth about the manuscript), who has it from Rip, who in the beginning used to vary on some points every time he told it.

So, it is impossible to identify and deconstruct the exact identity of the narrator of "Rip Van Winkle." The irony being that everytime Irving insists on the truth of the story he is actually denying it.

Washington Irving had a genius for inventing comic fictional narrators.  In fact, he did not sign his real name to his work until he was over fifty.  He had two narrators, Jonathan Oldstyle,...

The narrator of "Rip Van Winkle" was Diedrich Knickerbocker. It's actually Washington Irving pen name.