Affordable housing in the Seaport? That’s the plan.

The Massachusetts Port Authority has reached a deal to build a residential project like no other in the city’s priciest neighborhood: a tower with 200 apartments, all of them income-restricted.

The Massport board on Thursday picked a team led by Boston-based housing developer The Community Builders to build a 15-story tower on D Street, next to the port authority’s parking garage. While some of the luxury residential buildings in the area include city-mandated income-restricted units, Massport officials said this would be the first in which all units rent for below-market rates.

With all the land it controls in the neighborhood, Massport has been a key player in the Seaport’s rapid development. For example, this apartment tower would go up next to the luxury Waterside Place apartment complex and the high-end Omni hotel, both on Massport land. The port authority started looking for affordable housing developers for this site nearly two years ago, to help tackle the city’s affordable housing crisis.

“We wanted to do our part to be part of the solution,” Massport chief executive Lisa Wieland said. “This is the first mixed-income project of its kind on the South Boston waterfront.”

Massport officials narrowed the bidders to a list of five finalists in mid-2022, and applied its usual four-factor formula when rating them — with an important twist. Massport typically weighs these equally: the team’s track record, the team’s diversity, the project design and programming, and the financial return to the port authority. In this case, Massport replaced that last factor with the project’s affordability. Wieland said Massport will charge only a minimal fee for the use of the land, to cover maintenance and other operating costs.

“This was just such an important project to do that we were willing to make the trade off around the financial piece that we would normally look for,” Wieland said.

Wieland said the winning project scored high in all criteria, including diversity, setting the proposal apart from its competitors. The Community Builders is developing the $170 million, 224,000-square-foot project through a joint venture with the Menkiti Group, a Black-owned development firm in Washington, D.C. They’ve brought in several firms owned by people of color and women as co-developers or contractors. The tower’s base would include 15,000 square feet devoted to childcare and retail, and the building would be all-electric, with solar panels on the roof.

The apartments would be made available based on four different income ranges, ranging from a maximum of 30 percent of area median income for the least expensive units (currently $44,520 for a family of four) up to 120 percent ($178,080). Monthly rents would likely range from $950 to $3,000-plus, depending on the household’s income and size.

“This is something, if done correctly, [that] really adds to the overall fabric of what the Seaport neighborhood can be,” said Bo Menkiti, a Somerville native now based in Washington.

Andrew Hargens, Massport’s chief development officer, said it could take three years for the developers to secure permits and financing, before construction would begin. Massport officials expect the developers will seek state and federal affordable housing subsidies.

“It’s really visionary for Massport to stake a claim and say, ‘There’s room for all people that love Boston and may work in it,’” said Bart Mitchell, chief executive of The Community Builders. “How can we make this everybody’s neighborhood?”