I assumed that Harry Carpenter sounds too much like hairy carpenter.

  LOL 

To get back on topic, Marcone is not his real name either.  I had assumed his real name would be something in the order of Gianmarco Something (Rossi maybe, as that's the Italian equivalent of Smith?  ).  The suffix -one is Italian for "big", so Gianmarco becomes John Marco(ne), implying that he is bigger in his new persona than he was before.  Etymology, ftw!

Or, of course, he COULD just be called Marcone because he's a Mafia boss and his name is (sort of) like Capone...