At the start of World War I, Karbyshev was involved in combat operations in the Carpathians under General Aleksei Brusilov’s 8th Army on the Southwestern Front. At first he was the divisions' engineer for the 78th and the 69th Infantry Divisions, later chief of engineer service for the 22nd Finland Riflemen Corps. In early 1915, he was at the Siege of Przemyśl, where he was wounded in the leg. He was decorated with the Order of St. Anne for bravery and promoted to lieutenant colonel. In 1916, he participated in the Brusilov Offensive. With the February Revolution and the collapse of the Russian Empire, Karbyshev joined the local Red Guard in December 1917 while stationed at Mogilev-Podolsky (today Ukraine). From 1918, he was an officer in the Bolshevik Red Army.