… but he’s not sure what to call it:

The idea of taking a long roll of bread (like a French baguette or an Italian ciabatta), slicing it lengthwise, and filling it with an assortment of meats, cheeses, vegetables, condiments, and sauces must have occurred to many people in many places over the years, but in the United States such sandwiches have been associated with Italians since the early 20th century.
The ingredients vary from community to community (the New Orleans version the muffuletta has olive salad as a crucial component, for example). And the names are, for the most part, equally local. The Wikipedia page takes submarine sandwich (or sub) to be the closest thing to a generic term for the family, though it lists many local variants. So do Dave Wilton’s article “A Hoagie by Any Other Name” (Verbatim 28.3, Autumn 2003) and Barry Popik’s blog entry for “Submarine Sandwich (Sub Sandwich)” (April 5, 2008).
[I first knew these sandwiches as Italian sandwiches (in the Reading PA area in the 40s and 50s) — vulgarly called by their near-rhyming name wop jobs — but then cultural influences from southern New Jersey and Philadelphia gave us hoagies, and from New York City, submarine sandwiches or subs. At Princeton, we consumed grinders, using a name we associated with grinding (studying hard) — there was a Student Grinder Agency that delivered the sandwiches to men studying in their rooms — though that connection is surely historically inaccurate.]