[2] After the Revolutionary War "slavery actually strengthened in Kings County", due to its profitability in what was then the breadbasket to nearby New York City.

In 1838, James Weeks purchased a part of the Lefferts estate to create Weeksville, which, Wellman writes, “represented a refusal to live … ‘in the shadow of slavery.

[13] In 1918 and in 1920, the Fort Greene chapter of the Daughters of the American Revolution opened the house as a museum[14] and installed a “revolutionary” cannon from Governor's Island in the front yard.

Local department store Abraham & Straus announced in January 1965 that it would establish a children's farm next to the Lefferts Historic House to celebrate the park's centennial.

[24] Lefferts Historic House operates a children's museum highlighting of the Leffertses’ family life in Kings County over three centuries[25] including the Dutch and Native Americans who lived in the area before the structure was built.

[27] As of March 2021, the museum was closed because the house's roof, exterior, drainage system, and paths were being restored by Prospect Park Alliance.

On Father's Day and on Open House New York weekends, there are additional behind the scenes tours of the attic and basement areas.