WinnCompanies and the Boston Housing Authority (BHA) secured financing for redevelopment of the 35-building Mary Ellen McCormack complex.

The deal marks the first step in an effort to revitalize the Depression-era affordable-housing community into an expansive mixed-use project.

This first building, designated as “Building A,” will provide 37 one-bedroom units, 44 two-bedroom units, 12 three-bedroom units and one four-bedroom unit, all reserved for low-income families currently living at the Mary Ellen McCormack complex. Developers will also create a Veterans park, tot lot and splash pad.

Plans include neighborhood enhancements like a two-way separated bike lane, trees to line streets and road reconfigurations that improve pedestrian safety.

“For almost nine decades, Mary Ellen McCormack has been a cornerstone of Boston’s commitment to affordable housing,” said Boston Mayor Michelle Wu in a statement. “Today, we take a major step forward in ensuring that this historic community remains a vibrant, inclusive home for generations to come. This first phase of redevelopment will deliver modern, sustainable housing while strengthening connections to the surrounding neighborhood, enhancing public spaces and building a more resilient future for South Boston.”

Preliminary site work is underway, and Building A is set for completion in fall of 2026.

Upon completion of Building A, developers plan to pursue funding for Building B, featuring 300 mixed-income apartments, and Building C, featuring 196 mixed-income apartments, a majority of which will be reserved for senior citizens.

Ultimately, developers hope a decades-long transformation of the complex will create 3,300 units of mixed-income housing, 70,000 square feet of retail space and a community center operated in partnership with the Greater Boston YMCA.

The demolition process for existing buildings will take place in phases to allow most existing households to move into new apartments right away. The BHA will retain ownership of the land while WinnCompanies will manage, own and maintain the buildings.

“This first building jumpstarts an ambitious and inspired undertaking many years in the making that will ultimately give rise to a new mixed-income and mixed-use neighborhood,” said WinnCompanies CEO Gilbert Winn in a press release. “This community of opportunity will serve as a national model in how it thoughtfully fosters economic, social and environmental success over the long term for its 9,000 residents and surrounding Boston neighborhoods.”