The Knox's third son, Thomas Forster Knox (1849-1919) followed his father and older brother into business, and became prominent in the Commercial Banking Company of Sydney. Thomas also became a manager of Dalgety & Co., a large and extraordinarily successful joint-stock enterprise established in 1884 and encompassing interests in wool, stock, land and shipping. Of their other two sons, George (1845-1888) was a lawyer; and Adrian (1863-1932) was Chief Justice of the High Court of Australia from 1919 to 1930.