In the Balkan Wars, he was the Chief of Staff of the 1st Army, which scored huge success in battles of Kumanovo, Bitola (First Balkan War) and Bregalnica (Second Balkan War). Given that the commander was the militarily infinitely less experienced crown prince Alexander who had to rely heavily on his chief of staff - the appointment made him effectively the commander of the army. He took part in peace negotiations with Turkey, held in London in 1913, as a military expert in the Serbian Government delegation.