The store, the first of its kind for the company in New Zealand, was officially opened yesterday.
It has been trading since Saturday.
Mr Harper said the store came together in just 12 weeks after his visit, when he was "inspired by the space".
As the 75-year-old company's first foray into books, the store also sold CDs, DVDs and vinyl, along with musical merchandise.
It also had a cafe.
He hoped it would be "the first of many" in New Zealand.
Dunedin was chosen for the maiden store because it was a "literary town" and when the company contacted suppliers, they all agreed.
"My gut feel is it's a good book town."
Customer Russell Mackintosh, of Wanaka, thought the touch-screen listening posts were "awesome" and "fast" and the "fresh, funky, minimalistic" interior appealed to him.
The one store filled three retail spaces within Wall Street, leaving just one left for lease.
Dunedin city councillor Richard Walls said "big things don't happen in small spaces" and was pleased to be part of the store's launch and to have another major retailer in the mall.
"Wall Street is now humming and the critics have gone away."
Another new move for Marbecks was introducing a music download service on its online store, due to be launched next month.
