Knyphausen led the Hessian troops in the Battles of White Plains, Fort Washington, Brandywine, Germantown, Springfield, and Monmouth. In 1779 and 1780, he commanded British-held New York City. When Heister left for Germany, Knyphausen took command of the German troops serving under Sir William Howe. Because of Knyphausen's seniority, British officers held dormant commissions outranking him in case the British commander became disabled. Despite this, Knyphausen was trusted by his British superiors.