William K. Vanderbilt (1849-1920) was the second son of William Henry Vanderbilt and the grandson of Commodore Cornelius Vanderbilt, patriarch of the Vanderbilt dynasty. William K. Vanderbilt assisted his older brother, Cornelius Vanderbilt II, and his younger brother, Frederick W. Vanderbilt, in managing the family's vast shipping and railroad empire.
William K. Vanderbilt and his wife, Alva Vanderbilt, were leaders of upper-class Newport society. William K. Vanderbilt hired architect Richard Morris Hunt to design and build a marble palace on Bellevue Avenue as a birthday gift for Alva.
Marble House was modeled after the Petit Trianon at Versailles. Estimated at $11 million, the home featured 500,000 cubic feet of white marble. Custom-made furnishings by J. Allard and Sons of Paris decorated the interior. The Vanderbilts employed a summer staff of 36 butlers, maids, coachmen, and footmen, who wore maroon livery.
Like many men of America's upper class, William K. Vanderbilt spent his time engaging in leisure sports such as yachting, auto racing, and horse racing. The Vanderbilts frequently took long cruises aboard Alva, one of the largest yachts in the world when it was built in 1886.
Eager to establish ties with English nobility, Alva arranged a marriage for their daughter, Consuelo Vanderbilt, to the Ninth Duke of Marlborough. The marriage was an unhappy one and was annulled in the 1920s. Their son, William K. Vanderbilt Jr., was an avid auto racer. Their son, Harold Vanderbilt, was an accomplished yachtsman.
William K. and Alva Vanderbilt divorced in 1895. Alva retained ownership of Marble House. She later married Oliver H. P. Belmont and moved to Belcourt Castle at the end of Bellevue Avenue.
Harold Vanderbilt assisted the Preservation Society of Newport County in purchasing Marble House and opening it as a museum.