Soemu Toyoda was born in Japan in 1885. He graduated from the Naval Academy in 1905 and joined the Japanese Navy and by 1941 had reached the rank of admiral and was commander of the Kure Naval Station.

In November 1942 he became a member of the Supreme War Council and in May 1943 he took command of the Yokosuka Naval Base.

After the death of Admiral Mineichi Koga Toyoda was appointed Commander in Chief of the Combined Fleet in May 1944. The following month he implemented Plan A-Go but it resulted in the heavy defeat of Jisaburo Ozawa in the Battle of the Philippine Sea (19-20 June).

As a member of the Supreme War Council Toyoda argued against Emperor Hirohito desire for a negotiated peace after the dropping of the atom bombs on Hiroshima and Nagasaki in August 1945. Soemu Toyoda died in 1957.