Through his son Matthew's daughter, Caroline Slidell (née Perry) Belmont, he was the great-grandfather of statesman Perry Belmont (1851–1947), who served as a United States Representative from New York and the United States Minister to Spain, and also served as an officer in the U.S. Army during both the Spanish–American War and World War I. August Belmont Jr. (1853–1924), was an American financier, the builder of New York's Belmont Park racetrack, and a major owner/breeder of Thoroughbred racehorses. Oliver Hazard Perry Belmont (1858–1908) was a wealthy American socialite and United States Representative from New York; he was the second husband of Alva Vanderbilt Belmont.
