Werner's first assignment in the Seven Years' War was to advance with 300 riders from Glatz around the rear of the Austrian army commanded by Octavio Piccolomini. During the invasion of Bohemia, he distinguished himself in the Battle of Schleissitz.. In February 1757 he became Inhaber (Proprietor) of the Brown Hussars and, in the Battle of Prague, he was part of the left wing reserve commanded by Hans Joachim von Zieten. In the final attack of the reserve, Werner's regiment formed the lead. In the Battle of Kolin, he was again on the left wing. After the battle, he was sent to Lausitz to join the army of the Duke of Bevern. Here, in action at Klettendorf, he routed two Croatian battalions. On 22 November 1757, at the Battle of Breslau, he was again on the left wing under Hans Joachim von Zieten, where he fought in the area of Kleinburg.