Karl Ferdinand von Hagen, also called Karl Ferdinand von Geist (born 1711; died 19 February 1759 in Bautzen), was a Prussian major general and chief of Infantry Regiment No.

Karl Ferdinand von Hagen was married to a woman from the Behr family; she predeceased him (breast cancer) in Potsdam in January 1756,[1] and he left no heirs.

On 4 August 1740 he became second lieutenant and joined the first battalion of the life regiment of the new king Frederick II.

Hagen received command of a grenadier battalion in the Second Silesian War, this time from companies of Regiments No.

[2] On 27 October 1745, he took over the company of Lieutenant-Colonel von Wedel, who had fallen in the Battle of Soor.