Yumashev was the son of a clerk. In 1910, he was expelled from the fifth grade of school, due to his family being unable to afford school fees. At the age of 15, he began to work as a shoemaker, worker at a cement factory and delivery man in the administration of the Transcaucasian Railways. After the death of his father, he moved with his mother to the village of
Kapustin Yar in Astrakhan province, where he began to work as a clerk of a volost government.
From August 1920, Yumashev served in the Baltic Fleet. From 1920 to 1921, he was the commander of an artillery unit on the battleship
Marat, before serving as assistant commander of the ship. During the Kronstadt Uprising in March 1921, he was arrested by the rebels and was in prison until the end of the storming of the fortress by the Red Army.
In 1924 he took part in the first long-distance cruise of the Soviet fleet, which involved the passage of the Vorovskiy messenger ship from Arkhangelsk to Vladivostok. In 1925, he educated at special courses for commanding officers of the fleet. Yumashev served on the destroyers Lenin and Voikov, which was assigned to the Baltic Fleet. He served as second assistant to the commander of the battleship Marat. in 1932.
In 1926 he transferred to the Black Sea Fleet as captain of the cruiser Komintern. He subsequently commanded the cruiser Profintern and destroyer flotillas. On 1932, he attended tactical courses for commanders of ships at the Naval Academy. With the introduction of personal military ranks in the USSR, by order of the People's Commissar of Defense of the USSR No. 2488 of November 28, 1935, I. S. Yumashev was awarded the military rank of flagship of the 2nd rank. In September 1937, he became chief of staff of the Black Sea Fleet and in January 1938 commander of the Black Sea Fleet.
World War II
In March 1939, he became commander of the Pacific Fleet and commanded it until 1947. He made a great contribution to the development and strengthening of the fleet, by constructing naval bases, airfields and coastal defense in the Soviet Far East. On June 4, 1940, he was promoted to the rank of Vice Admiral and on May 31, 1943, he was awarded the rank of Admiral.
For commanding the fleet in the battles with Japanese troops, on September 14, 1945, he was awarded the title of Hero of the Soviet Union and the Order of Lenin.
Post war
In 1947 he was promoted to Commander in Chief of the Soviet Navy and in 1950 became Minister of the Navy, replaced one year later by Nikolai Gerasimovich Kuznetsov. Since 1951 he was director of the Naval Academy. Yumashev retired in 1957 and died in Leningrad in 1972.