Background
He was born a member of the Denhoff family, a noble family of Prussian origin (the German family name is Dönhoff).
He was born a member of the Denhoff family, a noble family of Prussian origin (the German family name is Dönhoff).
He came from Livonia and for services to George William, Elector of Brandenburg, he established his residence in Waldau near Königsberg. He was the brother of Gerhard Dönhoff and Kaspar von Dönhoff. Dönhoff was castellan of Pärnu (Parnawa) from 1635, voivode of Parnawa from 1640, starost of Tartu (Derpsk), Telšiai (Telszew) and of Waldau in the Pregolya River valley in Duchy of Prussia.
Dönhoff belonged to the commission which from 1625 worked for a peace agreement between Sweden and Poland.
He was also instrumental in the negotiations at the peace of Altmark and at Sztumska Wieś. Dönhoff became Count (Reichsgraf) of the Holy Roman Empire since 1633.