John Dreyfuss, the Georgetown sculptor who spent nearly two decades restoring one of the neighborhood's oldest mansions, died Saturday, Nov. 7, at age 77.

Dreyfuss was born in Washington in January 1949 to Edmund and Lorraine Dreyfuss, The Georgetowner reported. A fourth-generation Washingtonian, he attended Wilson (now Jackson-Reed) High School, the University of Pennsylvania and Harvard University's Graduate School of Design.

His father, Edmund Dreyfuss, founded the D.C. architectural firm Edmund W. Dreyfuss and Associates and purchased Halcyon House at 3400 Prospect St. NW from Georgetown University in 1966. The younger Dreyfuss took over the restoration of the mansion in 1978. The project consumed almost two decades.

The house, originally built by Benjamin Stoddert, the nation's first secretary of the Navy, had been heavily altered after Mark Twain's nephew Albert Clemens bought it in 1900. Clemens added wings, a ballroom and a chapel, enclosing the original Georgian structure on three sides. A Historic American Building survey called the changes "disfiguring it beyond credibility," according to a 1995 New York Times profile of the restoration.

Dreyfuss returned to Washington in 1978 from a sculpture apprenticeship in Connecticut because of his father's illness, the Times reported. He took over daily management of Halcyon House. After his father died in 1982, Dreyfuss assumed full responsibility for the restoration. He moved his sculpture studio into the ballroom, and he and his wife camped out in a tiny wing apartment with their bed in the kitchen.

The project nearly stalled several times because of money shortages and zoning and architectural review board problems, the Georgetowner reported. At one point, the partnership that owned the property discussed giving Halcyon House to the National Trust for Historic Preservation. "But they respectfully declined," Dreyfuss told the Times with a grin.

The house was in dire shape. "It was literally falling down," Dreyfuss said in the 1995 Times article. "There was decaying brickwork, rotting window sills, sagging timbers; the roof was imploding …"

He called the painstaking work of removing layers of later additions "unraveling the Gordian knot."

Wendy Charles, former executive director of Halcyon House, told the Georgetowner that Dreyfuss's persistence defined him. "What I can say about John is that he was very dogged about his projects," Charles said. "And I would say that his greatest project, obviously, is Halcyon House."

Beyond the mansion, Dreyfuss built a sculpture career that reached well past Georgetown. Charles told the Georgetowner his works stretched "from M Street all the way to Dubai and elsewhere" and were purchased by governments and art enthusiasts. His "Inventions" series, six freestanding sculptures in white-painted reinforced fiberglass, is part of the Kreeger Museum's outdoor collection, encircling the museum's Reflecting Pool.

Art gallery owner Chris Murray, Dreyfuss's best friend, recalled meeting him for the first time at Halcyon House when it was still a crumbling boarding house. Murray told the Georgetowner that a friend urged him to cross the street and knock on the door. "But I went up to the top floor. John took me up there. And he had a little sculptors' stand where you would make a wax model," Murray said.

Charles told the Georgetowner that Dreyfuss served on the boards of the Duke Ellington School of the Arts and the Francis Scott Key Foundation. He hosted student internships from Ellington and "always wanted to lend a hand and built friendships throughout the community," she said.

Halcyon House is listed on the National Register of Historic Places. It sold in November 2011 for $11 million. Washington Commanders owner Josh Harris acquired the property in 2026, the Wall Street Journal reported in January of that year.

Dreyfuss is survived by his wife, Carol Huh, and his brother, Kenneth Dreyfuss. Memorial service details had not been announced as of the Georgetowner's Nov. 9 report.