Through his family connections he met with the future King Frederick II of Prussia.
From 21 January 1752 to 1763 he was the president of the Prussian Supreme Tribunal, then the fourth senate of the Kammergericht.
[1] From 1762 to 1769, he was Henry Royal Prussian Postmaster General and Chief of the postal system.
He later rose to become directing minister, top civil servant and close personal advisor to Frederick the Great.
Henry IX married on 7 June 1743 in Dorth, near Deventer, to Amalie (1715-1787), a daughter of Count Charles of Wartensleben and Flodroff and his wife Johanna Margarita Huysseman von Cattendyck.