Outside the hotel, a fleet of new water taxis owned by Mr. Plank and modeled after Chesapeake Bay deadrise boats will soon ferry riders to Port Covington, the industrial South Baltimore waterfront area that is undergoing a $5.5 billion overhaul led by his real estate firm, Sagamore Development.
In September, the Baltimore City Council approved the use of $660 million in bonds to pay for infrastructure around that mixed-use project, which will include a new Under Armour campus. Under an arrangement called tax-increment financing, the bonds will be repaid through future property taxes generated by the development.
Sagamore is also hoping to receive nearly $600 million in state and federal investments for a light-rail extension, modifications to Interstate 95, and other improvements.
Many of the efforts from Mr. Plank, a former football player for the University of Maryland who founded Under Armour in 1996, have been greeted with open arms from the community.
But against the backdrop of all this rejuvenation, Under Armour’s stock has fallen about 48 percent in the past 12 months, as the company struggled in the face of a quickly changing retail industry. Its chief financial officer, Chip Molloy, resigned in February. In April, the company reported its first quarterly loss as a public company.
Mr. Plank, responding to questions by email, said he was fully focused on Under Armour and left the day-to-day work of Plank Industries to his employees.
“I am incredibly proud of the Plank Industries team for all that they have built and of the economic impact we have been able to have here in Baltimore,” he said.
Some people have raised concerns about the tax-increment financing deal, the largest in city history. Critics say that the subsidy is too big for a business with resources like Mr. Plank’s and that the city should focus on more critical needs, like schools. Others questioned whether agreements on compensation and affordable housing were adequate — and why there was no independent analysis of the numbers.
The former councilman Carl Stokes, who ultimately voted in favor of the deal, said he still wondered why his peers were eager to push it through without pursuing that analysis.
“Kevin’s been a good guy for the city of Baltimore, but he himself would not O.K. a deal that he didn’t vet,” he said.
There is no doubt, though, that Mr. Plank has managed to make sweeping changes to the downtown area. And even to those closely involved, it is almost unthinkable that all this development flowed from a horse farm in Glyndon, Md., less than 30 miles to the northwest.
Wanting to jump-start Maryland’s once-flourishing horse racing industry, Mr. Plank purchased Sagamore Farm and set out to restore it to its heyday under the racing industry titan Alfred Gwynne Vanderbilt.
Mr. Plank set a lofty goal for Sagamore — to win a Triple Crown — one that Vanderbilt, who died in 1999, was unable to accomplish, even with Native Dancer, one of the most celebrated horses ever. So far the highlight of Mr. Plank’s ownership is Shared Account’s victory in the $2 million Breeders’ Cup Filly and Mare Turf in 2010.