Telegin joined the Red Army in 1918 and fought in the Russian Civil War, becoming a member of the Russian Communist Party (Bolsheviks) in 1919. He served as a Regimental Commissar assistant. In 1931 he graduated from the Lenin Military-Political Academy. At first he was a political officer in the NKVD, and later was transferred to the Army. He was present at the Battle of Lake Khasan and took part in the Winter War. In 1940 he returned to the NKVD, and soon was assigned to the army again. On the eve of the German invasion he was a Brigade Commissar.