Emi Hisamori served as a bushō during the Sengoku period. Hisamori served as a retainer of the Amago clan and as the lord of Hayashino Castle in Mimasaka Province.
The Emi clan was an offshoot of the Sugawara clan, descending Sugawara Shoki, the grandson of Sugawara no Michizane. The family took root in Emi-no-shō in the Aida District of Mimasaka, becoming an powerful kokujin, or provincial landowners, controlling several districts in the eastern portion of Mimasaka.
In 1532, Amago Tsunehisa, the sengoku daimyō in the Sanin Region, ordered his lineal grandson, Amago Haruhisa, to invade Mimasaka. The Amago clan established marital ties with the Ōgawara clan, a branch of the Miura clan; and, in 1548, brought them under their command by having a member of the Miura clan inherit the headship of the clan and recognize the rights to their territory based at Katsuyama Castle in the Mashima District of Mimasaka. By this means, the Emi clan became subordinate to the Amago, while the Amago dispatched Kawazoe Hisamori, Uyama Motoaki(?), Uyama Hida-no-kami and others to serve as their direct retainers based in Mimasaka, governing the entire province. This allowed the Amago control over the strategically important Hayashino Castle (Kurashiki Castle) and its environs in eastern Mimasaka ruled by the Emi clan, serving as a buffer zone to contain the Uragami clan of Bizen Province. Amidst these circumstances, Hisamori arose as the chief of the Emi clan. In particular, he acted with tremendous energy in Mimasaka, defeating multiple invasions by Uragami Munekage and compelling the surrender of Gotō Katsumoto, the lord of Mitsuboshi Castle, who rebelled against the Amago.
However, in the twelfth month of 1560, following the death of Amago Haruhisa, the situation dramatically changed. Under Haruhisa’s son, Amago Yoshihisa, the home province of the Amago in Izumo became vulnerable so the generals who had earlier be stationed in neighboring provinces were summoned back to Izumo. In an effort to take advantage of the situation, Gotō Katsumoto rebelled again, but, was stopped by Hisamori who remained steadfast in his loyalty to the Amago until the final decimation of the clan. After the demise of the Amago clan, Hisamori temporarily built an independent base of power, but, in 1569, after Tachihara Hisatsuna and Yamanaka Yukimori backed Amago Katsuhisa in a bid to revive the Amago clan in Izumo, Hisamori joined the effort on behalf of the Amago revival army. This campaign came to an end after a loss by the Amago revival army at the Battle of Fubeyama in 1570.
Thereafter, the Emi clan weakened after attacks by the Ukita clan who were aligned with the Mōri, while its members came under the command of Togawa Hideyasu, a retainer of the Ukita, and survived as village headmen until the Edo period. Based on writings from Amago Haruhisa and Amago Yoshihisa, the Emi clan was a critical presence for the Amago with respect to the rule of eastern Mimasaka and as a means to contain the Uragami of neighboring Bizen Province. Meanwhile, the backing of the powerful Amago as a leading daimyō of the Sanin Region benefited the Emi clan in their rule of the Kurashiki area of eastern Mimasaka.