Born at Baynton House in East Coulston, Wiltshire, he was the second son of Walter Long and his first wife Mary Anne, daughter of Archibald Colquhoun [REF].
In 1846 his elder brother Walter married 21-year-old Harriet Avarina Brunetta Herbert, only daughter and heiress of Captain Owen Herbert, of Dolforgan Hall, Montgomeryshire [REF].