Takō Nagatomo served as a bushō during the Sengoku period. As a retainer of the Utsunomiya, a daimyō family of Shimotsuke Province, he served as the lord of Takō Castle.
Nagatomo was born as the son of Takō Tatemasa, a retainer of the Utsunomiya from the late Muromachi to Sengoku periods. Nagatomo deployed for many battles and was recognized within the Utsunomiya family as the top commander.
The Takō were an illegitimate branch of the Utsunomiya. From their base at Takō Castle, the clan served for generations as senior retainers of the Utsunomiya, fighting on their behalf in battles across the province. The Takō supported the military operations of the Utsunomiya on a par with other powerful bands of bushi including the Kisei-ryōtō (a group comprised of members of the Mashiko and Haga clans) and the Ōsugatō (a group comprised of members of the Kimijima family including the Kazami, the Ubagai, the Ōmiya, and the Enshō).
On 9/17 of Tenbun 18 (1549), Nagatomo and his son, Takō Fusatomo, participated in the Battle of Kitsuregawa-Sōtomezaka. In this event, Nasu Takasuke led 300 soldiers to invade the territory of the Utsunomiya. As a result, upon orders from Ashikaga Haruuji, the Koga kubō, Utsunomiya Hisatsuna led an army of 2,500 men to deploy to the Kitsure River and engage in battle against the Nasu forces.
Initially, the Utsunomiya enjoyed an advantage based on their superior numbers, so Takasuke used troops lying in ambush in Sōtomezaka to create havoc for the Utsunomiya army, reversing the tide of the battle in favor of the Nasu. Nagatomo, Michikawa Tadachika (a retainer of the Kasama), and the Yokota brothers (five sons of Yokota Tsunamura who were retainers of the Yokota) fought valiantly, halting the assault by the Nasu army, but Tadachika and the Yokota brothers were killed in action. These individuals are known as the Five Brothers of the Yokota. In an effort to control his army amidst the chaos, Hisatsuna went to the front lines of the battle but died after being struck in the chest by an arrow shot by Ayugase Sanemitsu, a retainer of Iono Sukenobu. The battle ended in victory for the Nasu army led by Takasuke.
In 1557, owing to the efforts of Haga Takasada, a loyal retainer of the Utsunomiya, Utsunomiya Castle was recaptured from Mibu Tsunatake of the Mibu clan. Soon thereafter, in 1558, Nagao Kagetora (later known as Uesugi Kenshin) plotted with Ashina Moriuji of Aizu to invade Shimotsuke from Kōzuke Province. Combining forces with the Sano army led by Sano Toyotsuna, the invaders captured Gion Castle from the Oyama clan and Mibu Castle from the Mibu clan, but Nagatomo repelled their attempted assault against Takō Castle, an event known as the Battle of Takōgahara. Notable participants on the side of the Takō included Takō Fusatomo (Nagatomo’s son) and retainers such as Koyama Kanemoto, Yana Tomomitsu and Yana Yoshitomo (father and son), Ishizaki Michisue, Nozawa Yasutoki, Takagi Michishige, Ueno Suketomo, Izawa Tōtōmi-no-kami, and Kida Awaji-no-kami, along with reinforcements such Ubagai Yoshitane and Yasaka Naganori. The defenders killed many of the attacking forces including Sano Toyotsuna, a powerful figure in Shimotsuke serving in the vanguard of the Uesugi. The Takō army pursued members of the Uesugi who were fleeing in defeat as far as Jōshū-Shiroi in Kōzuke Province until, through the mediation of Ōta Sukemasa, the opposing armies settled.
In 1589, Nagatomo died and was succeeded by his son, Fusatomo.