Anayama Seigorō served as a bushō and member of the Anayama clan who governed Kawachi in Kai Province. Seigorō was the great uncle of Anayama Nobutada.
Seigorō was the son of Anayama Nobutō, whom he assassinated in 1513. Thereafter, he does not appear in historical records, so it is presumed that he was killed in turn by his sibling, Anayama Nobukaze, who succeeded his father.
The daughter of Anayama Nobutō resided in Kawada, the homeland of the Kai-Takeda clan at the time. This daughter may have been wed to Takeda Nobumasa, a powerful retainer of the Takeda family. Nobutō maintained friendly relations with the Takeda family. However, it has been confirmed that Nobutō had close relations with Imagawa Ujichika and Hōjō Sōun, so Nobutō had relations with both the Takeda and the Imagawa. Nobutō may have had conflict with Seigorō with respect to relations with Takeda Nobutora, a sengoku daimyō and the eighteenth head of the Takeda clan in Kai Province. After Nobutō’s death, Nobukaze dissolved the subordinate relationship of the Anayama clan with the Takeda, and joined the Imagawa instead. Two years later, he cooperated in the invasion of Kai by Imagawa Ujichika.