From May 1919, Iovlev served as a Red Army man and platoon commander in the 104th Rifle Regiment of the 12th Rifle Division. He fought on the Southern Front with the unit against the Armed Forces of South Russia on the Don River, then in the Voronezh–Kastornoye and Donbass Operations. In the winter of 1919–1920 he fell ill with typhoid and was hospitalized. Sent to study at the one-year Military School of the Eastern Front at Samara in spring 1920, he served on the Turkestan Front in the fighting for Bukhara with a cadet detachment drawn from the school. After graduating from the school, Iovlev became chief of the administrative and mobilization directorate of the Revolutionary Military Council of the puppet Khorezm Soviet Republic in May 1921. Participating in the suppression of the Basmachi movement, he served as assistant chief of the operational section of the staff of the Samarkand Operational Group of Forces from August 1922.