Duncan was born in 1795 in Lismore, Scotland, the son of unknown parents.
His wife was Mary Carmichael. They were married, but the date and place have not been found. Their ten known children were Alexander (1814-?), Duncan (1816-?), Ann (1817-?), Mary (1820-1894), Hugh (1823-1915), Archibald (1825-?), John (1826-?), Neil (1828-?), Dugald (c1830-1895) and Duncan (1833-1876).