Kelly’s Roast Beef  — an iconic Boston-based franchise that boasts of inventing the modern roast beef sandwich — is expanding beyond its hometown roots and current four locations.

Kelly’s is opening six restaurants with several franchise partners across New England and 37 on the east and west coasts of Florida, with three of them scheduled to open by the end of 2022 and 10 by the end of 2023.

Launching in the early 1950s from leftover roast beef for a wedding, Kelly’s is known for its Original Roast Beef sandwich, piled high with hand-sliced medium-rare sirloin, American cheese, mayonnaise, and James River barbecue sauce. Kelly’s also offers New England seafood classics, such as lobster rolls, fried clams and fried fish.

Despite the previous couple of challenging years across the restaurant business, Kelly’s Roast Beef Franchising CEO Neil Newcomb said prior success provided confidence for the concept’s scalability.

“We were successful in licensing our concept to the Boston Logan Airport,” Newcomb said. “This taught us that we can train others to execute our concept.”

Newcomb credits Kelly’s Roast Beef sandwiches’ signature flavor to using a unique cut of meat for their rare, thin-sliced roast beef.

“We use a cut that no one else uses because it is more tender but harder to use because the cook has to trim out a tendon half way through slicing,” he said. “We only season it with salt and pepper. The bun is buttered and grilled — it is a great combination.”

Newcomb said that growing from four Boston-area locations to restaurants spread across New England and Florida has not yet brought changes to supply relationships.

“So far we have not made any changes in purchasing,” he said. “I think the seafood is where we will have to get Boston products shipped. Belly on clams are not everywhere.”

Operating on a bigger playing field with its expanded market presence and regional reach presents Kelly’s Roast Beef with opportunities for sharpening some of its organizational focus.

"As we grow, we would like to build a corporate team where people can specialize in a job,” Newcomb said. “For instance, instead of purchasing being one thing an operator does, we can have purchasing be the one thing a purchasing specialist does.”