He became a protégé of Schwarzenberg and thus closely tied to the pro-Imperial faction in Brandenburg during the period of the Thirty Years' War.
Schwarzenberg entrusted him with raising Brandenburg's first-ever standing army as the head of General War Commissariat.
He became the Great Elector's President of the Privy Council (Prime Minister) and it was in this capacity that he raised the finances and organized the system under which a permanent standing army could be created for the first time.
His eldest son Christoph Caspar, by his first marriage, became a distinguished diplomat who was Brandenburg's Ambassador to France and negotiated the Peace of Oliva.
A minister of the Great Elector, von Blumenthal had profited handsomely from the war, and remodeled Schloss Stavenow [1] in the Baroque style.