Practised in Honolulu with father’s firm, Castle & Withington, later with Robertson, Castle & Anthony. Deputy commissioner in Siberia for American Red Cross, 1918. Field director for Hawaii and special representative for Japan, Hawaii, China, and Philippines for Red Cross.
Representative terrace legislature, 1911, senator, 1915-1917. Served on Honolulu Board of Supervisors. President Honolulu Rapid Transit Limited company, Honolulu Gas Limited company.
Manager of his father’s estate. Director in numerous Hawaiian corporations. Past president Hawaiian Tennis Association (won singles championship: 1908, 1910, 1911, 1917.
And doubles: 1911, 1916, 1919, 1920, 1921, 1922, 1924. Pitcher on Harvard baseball team.