Originally from Suruga province, Kajiwara entered the Genpei War fighting under Oba Kagechika, against the Minamoto. After the Taira victory at Ishibashiyama in 1181, he was sent to pursue the fleeing Minamoto no Yoritomo. Having discovered him, Kajiwara switched sides, leading his forces in another direction, and turning to Yoritomo's cause.
Three years later, Kajiwara would lead the forces of Minamoto no Yoshitsune and Yoritomo into battle against their cousin Yoshinaka, and against the Taira. Attached to Yoshitsune's force, Kajiwara reported back to Yoritomo on Yoshitsune's actions, in order to satisfy Yoritomo's suspicion and distrust of his brother. In one particular episode related in The Tale of the Heike, Kajiwara suggests, during the Battle of Yashima, that Yoshitsune equip the Minamoto ships with "reverse oars" should they need to retreat quickly. Yoshitsune responds with distaste to Kajiwara's advice, humiliating him by saying such an act would be cowardice. From that point until Yoritomo's death, the resentful Kajiwara did as much as he could to raise tensions between the brothers. His slander led Yoritomo, already suspicious of his younger brother, to eventually accuse Yoshitsune of plotting against the bakufu, which then led to his exile and eventual death. Even after this, when the shogunate was successfully and firmly established, Kajiwara still caused tensions at court. He accused Yuki Tomomitsu of plotting against the Shogun Minamoto no Yoriie; a number of members of the court tried to get rid of him, who eventually left for Suruga. The following year (1200), he was defeated and killed in battle along with his son Kagesue.
- Kodansha Encyclopedia of Japan. Tokyo: Kodansha Ltd.
- Sansom, George (1958). 'A History of Japan to 1334'. Stanford, California: Stanford University
- Samurai-archives.com Biography of Kajiwara Kagetoki.
- (French) Louis Frédéric, 'Le Japon, Histoire et civilisation', p. 530