Masatomi Kimura was born in Shizuoka, Shizuoka Prefecture, Japan on 6 December 1891 to the Kondo family, but he was adopted by the Kimura family and raised in Tottori Prefecture. He graduated from the Imperial Japanese Navy Academy with the 41st class, proving to be a mediocre student; he placed 107 out of 118 cadets. He became a lieutenant in 1920, a lieutenant commander in 1926, a commander in 1932, and a captain in 1937, captaining Suzuya during the Attack on Pearl Harbor. In November 1942, he was promoted to Rear Admiral, and he took commander of the 3rd Destroyer Squadron, being tasked with escorting eight troop transports to New Guinea in 1943. His fleet was attacked by the US Navy in the Battle of the Bismarck Sea, and all of his transports and four destroyers were sunk by the American and Australian bombers. He was rescued by the Shikinami after his flagship Shirayuki was sunk, and he would later be sent to evacuate the Imperial Japanese Army troops from the Aleutians. Kimura heroically ignored orders and remained on station until every last Japanese soldier was evacuated, and he was sent to escort reinforcements to Leyte and Mindoro in the Philippines. On 1 November 1945, after the war's end, he was promoted to Vice Admiral, and he entered the reserves nine days later. He worked in the salt industry after the war, and he died of stomach cancer in 1960 at the age of 68.