John Mack and his wife Christy are putting their 15,978-square-foot Upper East Side estate on the market for $80 million. The property, located at 165 East 70th Street, is a converted 1910 carriage house that the couple purchased in 2009 for $13.5 million. If the transaction closes at the asking price, it will dethrone the previous record-holding townhouse on 14 East 67th Street, which sold for $77.1 million in 2019.
The building’s history is as layered as its limestone façade. Originally constructed in 1902 for banker Henri Wertheim’s horses and staff, the structure was unusually wide for a Manhattan townhouse, measuring 33 by 100 feet. It later served Singer heir Stephen C. Clark as a garage and chauffeur’s quarters before Paul and Bunny Mellon used it as a private garage. When the Macks bought the property from Bunny Mellon, they found a distressed shell. “It still had the horse ramps and stalls, like a barn,” Christy Mack told The Wall Street Journal.
The couple spent six years transforming the garage into a 20-room residence. Christy Mack led the design, working with architecture firm Sawyer Berson and interior designer Eleanor LaSota. They kept the historic limestone exterior but added a floor and reinforced the structure with steel. The result is a home featuring quarter-sawn oak floors, heated terraces, a bulletproof front door, and a 13-seat soundproof theatre. A wine cellar holds over 6,300 bottles, while a 480-square-foot rooftop terrace offers unobstructed city views.
Mike Fabbri of The Agency, the listing agent, noted the home was a significant undertaking for a couple who had spent a decade searching for a move-in-ready Manhattan property. The Macks raised their children in Westchester County and ultimately decided to build their dream home rather than settle for existing inventory. The listing includes custom Holland & Sherry wallpapers, Brunschwig & Fils fabrics, and lighting from Armani and Ralph Pucci. A wellness area features a cold plunge, steam room, sauna, and gym.
The market reaction to the $80 million tag will be closely watched by luxury real estate analysts. If the price holds, it marks a significant shift in the upper echelon of New York residential sales. Buyers are expected to tour the property in the coming weeks, with offers anticipated before the end of the quarter. The sale will determine whether the Mack estate sets a new benchmark for upscale townhouses in the city.