Herman Adriaan van Karnebeek studied law at the University of Utrecht. A conservative liberal like his father, he served as Mayor of the Hague (1911-1918) before the staunchly pro-German Van Karnebeek became Minister of Foreign Affairs on 9 September 1918 in the first cabinet of jhr. Charles Ruijs de Beerenbrouck. He continued serving as Foreign Minister in the first cabinet of dr. Hendrik Colijn. He eventually resigned when his concept treaty with Belgium was rejected by a parliamentary majority (1 April 1927). From 1936 till his death in 1942 he served as chairman of the Carnegie Foundation.