Born during a turbulent era when power was shifting from the Kyoto nobility to local warrior lords, much of Kajiwara's life was set against a protracted conflict. To understand his life, a historical overview is needed. The son of a feudal lord of Sagami province, Kagetoki was born at a time when two great families - the Taira and Minamoto - vied for supremacy. Swept up in this struggle, Kajiwara was a pragmatic opportunist who shifted allegiance when advantageous. During the 1150's he supported the dominant Taira faction against the Minamotos. In 1160 Minamoto no Yoshitomo was defeated and his surviving family members exiled.

Yoshitomo's oldest son Yoritomo was sent to eastern Shizuoka prefecture. In a way which resembles the shogun Tokugawa Ieyasu's boyhood exile four hundred years later, Yoritomo gradually won the respect of those holding him hostage. In fact, around 1177 he married the daughter of a local lord who was supposed to be guarding him. By 1180 Yoritomo became confident enough to attack a Taira garrison near Mishima. Soon he faced a large number of Taira forces at Ishibashiyama in Kanagawa prefecture. Yoritomo's forces were badly beaten in this encounter. Thanks to Kajiwara Kagetoki, however, Yoritomo escaped, seeking refuge in the Kanto region.

Sobered by his defeat, Yoritomo forged an alliance of disgruntled feudal lords from eastern Japan. By 1182 he was again ready for battle. This time he successfully routed a large Taira force near the Fujikawa River. Kajiwara helped Yoritomo at that battle and became one of his close advisers.

Yoritomo then turned his attention to Kyoto. When news that Kiso no Yoshinaka had conquered the capital reached Yoritomo, he promptly dispatched forces towards the imperial city. Kajiwara and Yoritomo's half-brother Yoshitsune ousted Yoshinaka's forces. They then battled Taira forces in Shikoku and Kyuushuu. By 1185 the Taira family was completely eradicated and Minamoto no Yoritomo became de facto sovereign of Japan.

Soon internal squabbles within Yoritomo's government began to undermine its effectiveness. Kajiwara and Yoshitsune clashed over many administrative issues. When Yoshitsune accepted some imperial titles without consulting the shogun, Kajiwara fueled Yoritomo's doubts about his loyalty. Yoritomo, suspicious by nature, came to view Yoshitsune as a threat and in 1191 ordered him to commit suicide.

As a prominent figure in the new Kamakura government, Kajiwara incurred the ire of many. After Yoritomo passed away in 1199, Kajiwara's position became less tenable. For a brief time he was advisor to the second shogun, Yoriie. However, the young shogun never trusted Kajiwara and when Kajiwara tried to oust his rival Asamitsu Yuki from office, his plot backfired. Sixty-six ranking samurai presented a petition to the shogun to have Kajiwara expelled from Kamakura on Dec. 24, 1199. An order for his assassination was then dispatched to the Irie family of Shizuoka.

Kajiwara attempted to travel to Kyoto with 33 other samurai in an ill-fated attempt to help Takeda Ariyoshi conquer the capital. When he passed through the Seikenji Barrier in Okitsu on the night of January 20, 1200, samurai from the Yoshikawa, Rohara, Kudoh, Misawa, Iida, Funakoshi, and Yabe families were waiting. A fierce battle ensued. According to one account, Kajiwara and his retainers were killed near Kitsunegasaki, in western Shizuoka. Another account alleges that they fled to the hills of Oochi, were the surviving members of his entourage committed suicide when it was clear their cause was hopeless.

After Kajiwara's corpse was found, his head was severed and placed on a bamboo pole for others to leer at. The samurai families that sent his entourage to their deaths were well rewarded. Later, these families decided to build a temple to appease Kajiwara's spirit, since it was believed angry spirits would evoke ill fortune. Ryusenji Temple, which contained Kajiwara's bones, was constructed. In the Meiji Era that temple became deserted, and its relics were transferred to the neighboring Houkaiji Temple. Today there is a small shrine in Kajiwara's honor near the place where his head once hung from a spike.

Kogenji Temple, also located in Takahashi, has prayer tablets in honor of this warrior. In 1985 a committee was established in honor of Kajiwara and promote historical research.