Career
Until the 1648 Peace of Westphalia he distinguished himself as an able and daring cavalry leader and gained a reputation for brilliance and bravery, which in 1654 persuaded Elector Frederick William of Brandenburg to offer Derfflinger a senior position in his army. Derfflinger was supposedly a notorious drunkard who constantly drank Schnapps, but his fondness for alcohol did not impede his military abilities. A lifelong soldier, Derfflinger had no formal education, but was entrusted by the Elector with numerous important military tasks and played a central role in the reform of the Brandenburgian cavalry and artillery.
He had a very stormy relationship with Frederick William and argued with him incessantly, at one point quitting.
In order to gain back the Elector"s employ, he wrote down a list of incredible demands, which included a clause stipulating that no man charge into battle ahead of him and that he take a certain percentage of plunder and captured officers from every engagement. In 1674, Derfflinger was elevated to a Reichsfreiherr by Emperor Leopold I. A year later, he was decisive in defeating the Swedes and driving them out of Brandenburg: He impersonated a Swedish officer (a feat he was able to do because he had served in the armies of Sweden), and was able to convince the Swedes to open the gates of Rathenow, allowing him and 1,000 nearby dragoons to storm the fortress.
His last military campaign was in 1690 against King Louis XIV of France, when he was 84 years old. Derfflinger died at his estates in Gusow.
The Imperial German Navy"s battlecruiser SMS Derfflinger was named after him.