Shmidt joined the Red Army in 1918. He fought in the Russian Civil War. Shmidt served as commandant in Pryluky from January, attempting to establish Soviet power there. At one point, he was captured by anti-Soviet Ukrainians and was sentenced to death. He was wounded instead of being killed and during the German-Austrian occupation of Ukraine led the Bolshevik underground. In the fall of 1918 Shmidt formed a partisan group in the Pryluky area. The group became the 7th Sudzhansky (later 5th Soviet) Regiment, which became part of the 37th Rifle Division. In February 1919 Shmidt became commander of the 2nd Brigade in the division. In March, he met Hungarian Communist Tibor Szamuely, who recommended that Shmidt lead an expedition to help the Hungarian Soviet Republic. However, the expedition was never made.