Hasegawa Kyōsuke served as a bushō during the Sengoku period. Kyōsuke was the younger brother of Hasegawa Yoji and uncle of Hasegawa Hidekazu – a daimyō in Owari Province. He was commonly known as Ukon.
Kyōsuke initially served as a servant to Oda Nobunaga. In 1552, Kyōsuke participated as a foot soldier in the vanguard of the Battle of Akatsuka in which Nobunaga’s men fought against the forces of Yamaguchi Noriyoshi. In the beginning of the Eiroku era (1558 to 1570), Kyōsuke became a member of the akahoroshū – an elite division of mounted soldiers adorned with red capes.
In 1560, at the Battle of Okehazama, when Nobunaga began his initial march at dawn, Kyōsuke, along with Iwamuro Shigeyasu, Sawaki Yoshiyuki, Yamaguchi Hida-no-kami, and Katō Yasaburō were the only five accompanying him. In 1569, at the Battle of Ōkawachi Castle, Kyōsuke, Yoshiyuki, and others served as members of the unit to defend the main camp.
Later, Kyōsuke fell out of favor with Nobunaga so, along with Yoshiyuki, Hida-no-kami, and Yasaburō, absconded from the Oda family. Together, they approached Tokugawa Ieyasu for protection. The treatment he received at this time is unclear, but he did participate in the Battle of Mikata-ga-hara on 12/22 of 1572, and, together with Yoshiyuki, Hida-no-kami, and Yasaburō, died in battle.
According to one account, when Nobunaga killed his younger brother Nobukatsu (also known as Nobuyuki), Kyōsuke was one of three soldiers who cut him down; however, in the definitive biography of Nobunaga known as the Shinchō kōki, there is no account of this event so it cannot be confirmed.
His son, Shirōzaemon, returned to Owari and served under Hasegawa Hidekazu.