On 8 June 1764 he was made a member of the Gelderland delegation in the States General of the Dutch Republic, which he remained until 1782.
[2] On 15 August 1782 he was sent by the States-General to the peace negotiations between the participants in the American Revolutionary War in Fontainebleau as an Envoy Extraordinary and Minister Plenipotentiary (together with ambassador Mattheus Lestevenon) for the Republic to negotiate the 1784 treaty that ended the Fourth Anglo-Dutch War (to which he was a signatory).
While in France they negotiated the Treaty of Fontainebleau (1785) with Holy Roman Emperor Joseph II which maintained the continued closure of the Scheldt, in exchange for certain concessions from the Republic.
In 1787 he was recalled,[Note 2] but remained as a private citizen in France until 1792 (Rue Neuve des Mathurins).
[4] In May 1805 (after the Staatsbewind had been replaced by Grand Pensionary Rutger Jan Schimmelpenninck) he was again appointed envoy extraordinary to France where he helped negotiate the transfer of the Batavian Republic to the Kingdom of Holland.