In January 1633, as a reward for his service at Lützen, Knyphausen was appointed Field Marshal and commander-in-chief of all Swedish forces operating in Lower Saxony, an important side-theatre to the main Swedish operations in Southern Germany. In this role he served at the major Swedish victory at the Battle of Oldendorf in 1633. From 1633 to 1634 he participated in an unsuccessful Siege of Hildesheim. At the minor Battle of Haselünne in early 1636 he was killed. A distant relative, Edzard zu Innhausen und Knyphausen (1827–1908) was a noted politician.