A week later, the German Battalion was in action at Assunpink Creek where a number of its troops were captured, including Haussegger. The next day, the unit fought at Princeton. After Haussegger defected to the British, George Washington appointed the Prussian volunteer Henry Leonard d'Arendt to command the battalion. The battalion served with the 1st Virginia Brigade at Brandywine and Germantown in September and October 1777. The following June the German Battalion fought at Monmouth. Late in 1778, the unit was assigned to Edward Hand's brigade and served in the Sullivan Expedition in the summer of 1779. The battalion transferred to the New Jersey Brigade before being dissolved in January 1781.