After the battle of Kumanovo, he was promoted into a General. Prior to World War I, along with General Stepa Stepanovic, he planned out movements of the Serbian army which eventually pulled out a victory at the mountain of Cer and Kolubara. Mishich provided yet another victory at the Kolubara river beating the Austro-Hungarian army. Winning one of the greatest battles in the Serbian history, he was promoted into the rank of Duke. As the Serbian Army settled in Kosovo, in 1915, Mishich was eager to perform the counteroffensive actions. This was denied by the King, and the withdrawal of Serbian forces over Montenegro and Albania followed. At the Thessaloniki Front in 1916, he led the First Serbian Army which scored a victory and liberated Serbia and Yugoslavia.