As a reserve infantry officer Simić fought in both the Balkan Wars and in the Great War. During the First and Second Balkan War Simić was a reserve captain with the Supreme Command of the Serbian army. After the victory of the Serbian army in the Battle of Kumanovo he transferred to Skopje with the Supreme Command. In 1914 World War I broke out and Vasilije Simić was once again sent to serve with the Supreme Command of the Serbian army. From the autumn of 1915 the Serbian army and refugees were in a dire situation in Kosovo and Metohia. The Supreme Command decided on a retreat across Albania and Montenegro to the Adriatic coast to meet up with the Allied forces. After the Albanian Golgotha Vasilije M. Simić ended up on the island of Corfu, which housed the Serbian army, refugees, the national parliament, government and other institutions. With the Serbian army he breached the Salonika front and took part in the Battle of Kaymakchalan [11]. He participated in the liberation of Belgrade, Zagreb and Ljubljana.