He is a pinstripe-suit wearing auctioneer. He pretends to come from another country so people believe that he doesn't speak fluent English. Olaf constantly says "please" after and in the middle of every sentence. This is also done by Madame Lulu. He wears horse riding boots to cover up his tattoo, and a monocle to distort his eyebrow. Esmé Squalor was aware of Count Olaf's identity due to being trained by him.
Count Olaf's identity is revealed when he slips on a doily and his boots and monocle come off. He and Esmé run out of the auction hall and the audience that tries to chase them get into a hopeless tangle when slipping on the doilies and tumbling down.