Nagumo was born in the city of Yonezawa, Yamagata Prefecture in northern Japan in 1887.
He graduated from the 36th class of the IJN Academy in 1908, with a ranking of 8 out of a class of 191 cadets.
As a midshipman, he served in the protected cruisers Soya and Niitaka and the armored cruiser Nisshin.
After his promotion to ensign in 1910, he was assigned to cruiser Asama.

After attending torpedo and naval artillery schools, he was promoted to sub-lieutenant and served in the battleship Aki, followed by the destroyer Hatsuyuki.
In 1914, he was promoted to lieutenant and was assigned to the battlecruiser Kirishima, followed by the destroyer Sugi.
He was assigned his first command, the destroyer Kisaragi, on 15 December 1917.

Nagumo graduated from the Naval War College, and was promoted to lieutenant commander in 1920.
His specialty was torpedo and destroyer tactics.
From 1920 to 1921, he was captain of the destroyer Momi, but was soon sent to shore duty with various assignments by the IJN General Staff.
He became a commander in 1924.
From 1925 to 1926, Nagumo accompanied a Japanese mission to study naval warfare strategy, tactics, and equipment in Europe and the United States.

After his return to Japan, Nagumo was appointed captain of the river gunboat Saga from 20 March 1926 to 15 October 1926, followed by the gunboat Uji from 15 October 1926 to 15 November 1927.
He then
served as an instructor at the IJN Academy from 1927 to 1929.
Nagumo was promoted to captain in November 1929 and assumed command of the light cruiser Naka and from 1930 to 1931 was commander of the 11th Destroyer Division.
After serving in administrative positions from 1931 to 1933, he assumed command of the heavy cruiser Takao from 1933 to 1934, and the battleship Yamashiro from 1934 to 1935.
He was promoted to rear admiral on 1 November 1935.

As a rear admiral, Nagumo commanded the 8th Cruiser Division to support Imperial Japanese Army movements in China from the Yellow Sea.
As a leading officer of the militaristic Fleet Faction, he also received a boost in his career from political forces.

From 1937 to 1938, he was commandant of the Torpedo School, and from 1938 to 1939, he was commander of the 3rd Cruiser Division.
Nagumo was promoted to vice admiral on 15 November 1939.
From November 1940 to April 1941, Nagumo was commandant of the Naval War College.
Nagumo was born in the city of Yonezawa, Yamagata Prefecture in northern Japan in 1887. He graduated from the 36th class of the IJN Academy in 1908, with a ranking of 8 out of a class of 191 cadets. As a midshipman, he served in the protected cruisers Soya and Niitaka and the armored cruiser Nisshin. After his promotion to ensign in 1910, he was assigned to cruiser Asama.
After attending torpedo and naval artillery schools, he was promoted to sub-lieutenant and served in the battleship Aki, followed by the destroyer Hatsuyuki. In 1914, he was promoted to lieutenant and was assigned to the battlecruiser Kirishima, followed by the destroyer Sugi. He was assigned his first command, the destroyer Kisaragi, on 15 December 1917.
Nagumo graduated from the Naval War College, and was promoted to lieutenant commander in 1920. His specialty was torpedo and destroyer tactics. From 1920 to 1921, he was captain of the destroyer Momi, but was soon sent to shore duty with various assignments by the IJN General Staff. He became a commander in 1924. From 1925 to 1926, Nagumo accompanied a Japanese mission to study naval warfare strategy, tactics, and equipment in Europe and the United States.
After his return to Japan, Nagumo was appointed captain of the river gunboat Saga from 20 March 1926 to 15 October 1926, followed by the gunboat Uji from 15 October 1926 to 15 November 1927. He then
served as an instructor at the IJN Academy from 1927 to 1929. Nagumo was promoted to captain in November 1929 and assumed command of the light cruiser Naka and from 1930 to 1931 was commander of the 11th Destroyer Division. After serving in administrative positions from 1931 to 1933, he assumed command of the heavy cruiser Takao from 1933 to 1934, and the battleship Yamashiro from 1934 to 1935. He was promoted to rear admiral on 1 November 1935.
As a rear admiral, Nagumo commanded the 8th Cruiser Division to support Imperial Japanese Army movements in China from the Yellow Sea. As a leading officer of the militaristic Fleet Faction, he also received a boost in his career from political forces.
From 1937 to 1938, he was commandant of the Torpedo School, and from 1938 to 1939, he was commander of the 3rd Cruiser Division. Nagumo was promoted to vice admiral on 15 November 1939. From November 1940 to April 1941, Nagumo was commandant of the Naval War College.
Chūichi Nagumo