In 1931 Seiji Kimoto graduated from Tokyo University. In 1939 received Doctor of Medicine.
In 1944 was appointed assistant professor of medical department of theTokyo University, and then, in 1952, professor. In 1943 Seiji Kimoto attempted surgical treatment of heart disease, going deeper from his specialized field of surgery of blood vessels.
Originating a new method of anaesthesia, called "Hibernation Anaesthesia” which is conducted by selectively reingerating the brain, Seiji Kimoto succeeded in visible operation of the heart. For numbers of times he conducted successful operations to cut away aneurysm of the aorta in the field of blood vessel surgery and vessel transplantation.