In 1901 he became a member of the
German Student Corps called the Corps Palaio-Alsatia in
Strasbourg. After completing his studies, he worked as an
attaché in the
Foreign Office. From 1905 to 1917 as embassy or embassy secretary in
Washington, D.C.,
Constantinople,
Belgrade and
Rome, among others. He was friendly with
Lord Haldane while he was British
Secretary of State for War. Until the end of 1918 he was head of Department IV (News) in the Foreign Office with the rank of Ministerial Director. In 1907, while Councillor of the German Embassy, Baron von Stumm was blamed for a candid interview with German Emperor
Wilhelm II published in
Hulton's
Daily Dispatch (of which the authenticity was questioned). Von Stumm "had to leave the hunting trip he was on with
Reid to manage the ensuing 'mess'" as relayed by
American Ambassador Reid to President
Theodore Roosevelt. In 1919 he resigned from the diplomatic service as a legation councilor and from then on lived in
Neunkirchen so he could oversee his board membership in the family-owned Stumm group. He was a member of the supervisory board of the family ironworks, Neunkircher Eisenwerke AG, Homburger Eisenwerk AG and
Heydt's Bank AG in Berlin, as well as a member of the board of the coal mine
Zeche Minister Achenbach. After his father's death in 1925, he became the owner of
Schloss Rauischholzhausen, the manor in
Ebsdorfergrund,
Marburg-Biedenkopf,
Hesse (which his father had acquired in 1873). In 1928 he left Neunkirchen and from then on lived in
Ascona,
Locarno (on the shore of
Lake Maggiore in
Switzerland) or at Schloss Rauischholzhausen. ==Personal life==