Beginning at the age of fifteen, Sloane started working for the family carpet and furniture firm which was started by his father in 1843. In 1852, his uncle John W. Sloane joined the firm and it was renamed W. & J. Sloane. He later became a member of the firm, and in 1870 was sent west to San Francisco to establish the California branch of the firm. When the company was incorporated in 1891, Sloane became a director and remained on the board until his death. He later served as a senior director and treasurer of the company. In his father and brother's memory, Sloane donated $515,000 to Yale for a large physics laboratory known as the Sloane Physics Laboratory. He was a member of the New York Yacht Club, the Seawanhaka Corinthian Yacht Club, and the Pilgrim Club.
Personal life
In 1880, Sloane was married to Jessie Ann Robbins. Jessie was the daughter of Matilda Louisa Robbins and Daniel Cook Robbins, a partner in the wholesale drug firm of McKesson & Robbins. Together, they were the parents of two daughters:
Jessie M. Sloane, who married William Earl Dodge IV, the son of William E. Dodge III and Emeline Dodge, in 1905. They divorced and she married George Dunton Widener Jr. in 1917.
Emily Eleanor Sloane, who married Baron Amaury de La Grange, a French Senator, Under-Secretary of State of France, and Vice-President of the International Aviation Federation. He was held prisoner for five years during World War II by the Nazis.
On April 28, 1889, his wife divorced him so five hours later she could marry Perry Belmont, a U.S. Representative and former U.S. Minister to Spain. While Sloane was rumored to have been engaged, he never remarried. After a month's illness, Sloane died of pneumonia at the James T. Shewan house in Southampton, New York on September 18, 1937. After a funeral at St. Bartholomew's Church, he was buried at Woodlawn Cemetery in the Bronx. After his death, his paintings were sold at auction at the Parke-Bernet Galleries in New York in 1938.
Through his daughter Jessie, he was the grandfather of Diana Dodge, who married Frederick Martin Davies, a grandson of Daniel O'Neill, owner of the Pittsburgh Dispatch. Through his daughter Emily, he was the grandfather of Amicie de Nicolay, Marie de La Grange, who married Henry Baldwin Hyde in 1941, and Henry-Louis de La Grange, a musicologist and biographer of Gustav Mahler.