Nagatomi, known in his childhood as Kakuzō (覚蔵) and later Bankichi (蕃吉), was born in the clan's
Edo residence in 1803. He was the eldest son of the previous
daimyō,
Niwa Nagaakira by a concubine. At age 11, on the death of his father, he became
daimyō of Nihonmatsu. Due to his youth, he relied heavily on his
karō, Niwa Takaaki. He encouraged his retainers to excel in both martial and literary arts, and to that end, sponsored the opening of the
han school,
Keigakukan (敬学館). In 1822, he was forced to deploy domain forces to put down a peasant uprising. He also helped revive the domain's economic situation following a seven-year
string of famines during the
Tenpō era. His domain, together with
Aizu Domain, was placed in charge of security at the
Futtsu artillery emplacement by the
Tokugawa shogunate during the
Perry Expedition. Citing ill health, Nagatomi resigned his positions in 1858, and was succeeded by his sixth son
Niwa Nagakuni. Nagatomi was married to a granddaughter of
Arima Yoritaka of
Kurume Domain. His seventh son was adopted into the
Inaba clan, becoming
Inaba Masakuni,
daimyō of
Yodo Domain and a member of the
rōjū council. His either son was likewise adopted into the
Mizuno clan, becoming
Mizuno Katsutomo daimyō of
Yūki Domain, while one of his daughters became the official wife of
Tokugawa Yoshikatsu of
Owari Domain, and another married
Tokugawa Mochinaga, head of the
Hitotsubashi Tokugawa ==Notes==