Lifespan: Unknown to 5/20 of Tenbun 11 (1542)
Other Names: Tsuguyoshi, Yukinao
Rank: bushō, sengoku daimyō
Title: Governor of Tōtōmi
Father: Nikaidō Yukiakira
Siblings: Yukikage, Haruyuki
Children: Teruyuki, Yokota Yoshinobu
Nikaidō Haruyuki served as a bushō and sengoku daimyō of Mutsu Province during the Sengoku period. He was the fifth head of the Sukagawa-Nikaidō clan.
Haruyuki was born as the second son of Nikaidō Yukiakira, a bushō and the third head of the Sukagawa-Nikaidō clan.
He received one of the characters in his name from Ashikaga Yoshiharu, the twelfth shōgun of the Muromachi bakufu.
Following the death of his father, his older brother, Nikaidō Yukikage, died in 1504 so Haruyuki inherited the headship of the clan.
In 1534, when the Date clan fought against the Shirakawa-Yūki and Iwaki clans, Haruyuki allied with the Date and battled against the Shirakawa-Yūki. During this battle, he acquired a portion of the Shirakawa territory and his lineal heir, Nikaidō Teruyuki, received as his wife the younger sister of Date Harumune.
Haruyuki frequently quarreled with the Tamura, a sengoku daimyō family governing the Tamura District of Mutsu.
In 1542, he died of illness. Under another theory, he died in 1537.