Moore's first wife, Alice McLaughlin (1872–1897), was the daughter of Frank McLaughlin, former owner of the Philadelphia Times.
She gave birth to two children, and died 12 days after bearing the second:
daughter, Frances Sarah Preston, September 14, 1894 – early October 1921, who married Henri Marquisan and died in Paris, and
son, Samuel Preston, born July 5, 1897.

Moore married again on June 20, 1900 in Beverly, Massachusetts to Mabelle Florence Swift (1878–1933), daughter and heiress of Chicago meat packer Edwin C. Swift (a brother of Swift & Company founder Gustavus).
The couple had four more children, the first of whom died young:
son, Edwin Swift, November 25, 1901 – January 11, 1907 (aged 5),
son, Jasper, November 30, 1905 – 1969, in Duncan, British Columbia,
son, Clarence Jr, born January 20, 1910, who attended Eton and Harvard and married Joan Ashton Lindsley on December 28, 1932, and
son, Lloyd, born November 29, 1911, who married and was divorced from Eppes Bartow Preston (née Hawes; 1901–1981), daughter of U.S. senator Harry B. Hawes.

Moore asked architects Jules Henri de Sibour and Bruce Price in 1906 to design a mansion for his family on land his wife had bought in 1901.
Known as the Clarence Moore House, its construction was completed at 1746 Massachusetts Avenue NW in 1909.
Moore died three years later and his widow remarried in 1915 to Danish immigrant Aksel C.P. Wichfeld, a year before he was appointed to the Danish legation, afterward only using the mansion for diplomatic and social events.
She sold the property to the monarchy of Canada in 1927, after which it was used as a Canadian chancery and embassy.
Canada relocated their embassy to another property, officially opened in 1989, and sold the Massachusetts Avenue property in 1996 to the government of Uzbekistan, which also uses it as an embassy.

Though often cited as having the middle name "Bloomfield", Moore's birth, census, and passport records do not include a middle name.
When his daughter was born in 1894, her father's name was listed as "Clarence Samuel Preston Moore".
His name may have later been confused with that of another famous American of his time, archaeologist Clarence Bloomfield Moore (1852–1936).
Moore's first wife, Alice McLaughlin (1872–1897), was the daughter of Frank McLaughlin, former owner of the Philadelphia Times. She gave birth to two children, and died 12 days after bearing the second:
daughter, Frances Sarah Preston, September 14, 1894 – early October 1921, who married Henri Marquisan and died in Paris, and
son, Samuel Preston, born July 5, 1897.
Moore married again on June 20, 1900 in Beverly, Massachusetts to Mabelle Florence Swift (1878–1933), daughter and heiress of Chicago meat packer Edwin C. Swift (a brother of Swift & Company founder Gustavus). The couple had four more children, the first of whom died young:
son, Edwin Swift, November 25, 1901 – January 11, 1907 (aged 5),
son, Jasper, November 30, 1905 – 1969, in Duncan, British Columbia,
son, Clarence Jr, born January 20, 1910, who attended Eton and Harvard and married Joan Ashton Lindsley on December 28, 1932, and
son, Lloyd, born November 29, 1911, who married and was divorced from Eppes Bartow Preston (née Hawes; 1901–1981), daughter of U.S. senator Harry B. Hawes.
Moore asked architects Jules Henri de Sibour and Bruce Price in 1906 to design a mansion for his family on land his wife had bought in 1901. Known as the Clarence Moore House, its construction was completed at 1746 Massachusetts Avenue NW in 1909. Moore died three years later and his widow remarried in 1915 to Danish immigrant Aksel C.P. Wichfeld, a year before he was appointed to the Danish legation, afterward only using the mansion for diplomatic and social events. She sold the property to the monarchy of Canada in 1927, after which it was used as a Canadian chancery and embassy. Canada relocated their embassy to another property, officially opened in 1989, and sold the Massachusetts Avenue property in 1996 to the government of Uzbekistan, which also uses it as an embassy.
Though often cited as having the middle name "Bloomfield", Moore's birth, census, and passport records do not include a middle name. When his daughter was born in 1894, her father's name was listed as "Clarence Samuel Preston Moore". His name may have later been confused with that of another famous American of his time, archaeologist Clarence Bloomfield Moore (1852–1936).
Clarence Moore (businessman)