Kathleen or Katherine Geddes Benedict was born in Canada and emigrated to the United States in 1905. She became the second wife of Henry Harper Benedict (1844-1935), businessman and collector. They married in 1917.
The 1920 Manhattan census gives her name as Kathleen, her age as 36 (H.H. Benedict was 76); they were living with their daughter, seven year old Josephine K. Benedict and seven servants at East 75 Street. However the name is given as Katherine G. Benedict in 1930. Josephine married James Douglass Sharpe in 1937; she and her mother inherited Benedict's collection.
In 1960 her 19 year old grand-daughter Gamble ran away and married their 35 year old chauffeur, Andrei Porumbeanu, and this led to family disputes and lawsuits. The stress probably led to Mrs Benedict's death.
His wife and daughter inherited Benedict's collection, which they described to Frederick Coburn when he and Joseph Revillon were attempting to write a catalogue of Whistler's works on paper (24 November 1945, GUL Rev 1955). At her death, her estate was valued at about $30 milion. Some of her collection was auctioned at Sotheby's, London, in 1962-63.
Manhattan, New York, US census 1920 and 1930; 'Mrs Benedict, grandmother of Gamble, dies', 30 October 1961, Chicago Tribune, 30 Oct0ber 1961, part 3, p. 7, Chicago Tribune archives online; Auction catalogue, Mrs H. H. Benedict sale, Sotheby's, London, 21 November 1962; The Distinguished Collection of Old Master and Modern Engravings and Etchings of the Late Henry Harper Benedict, auction, Sotheby's, London, 1963; 'The H. H. Benedict Mansion -- No. 5 East 75th Street', Dayton in Manhattan, 14 March 2015, Blog.