Mera Shigekata served as a bushō during the Sengoku and Azuchi-Momoyama periods. He was a retainer of the Hyūga-Itō clan. Shigekata served as the lord of Suki Castle in the Motokata District of Hyūga Province. He was also the steward of Mitsuyama.
The Mera were originally a gōzoku, or wealthy family, from Merayama in the Kuma District of Higo Province. Later, some of the family joined the Kikuchi clan, adopting the Kikuchi surname, while others moved to Suki and Shiiba in Hyūga, becoming retainers of the Hyūga-Itō clan. The Suki-Mera were of a line of families serving as the high priests of shrines responsible for driving away the revengeful ghosts of the Hyūga-Itō.
In 1566, Shigekata was ordered by his lord, Itō Yoshisuke (a sengoku daimyō and the eleventh head of the Hyūga-Itō) to build Kobayashi Castle adjacent to the territory of the Shimazu clan of Satsuma Province. This was intended to contain the Shimazu as well as to serve as a forward operating base for an attack against Iino Castle held by the Shimazu. Shigekata was also appointed to serve as its lord so that he held both Suki and Kobayashi castles.
On 10/26 of Eiroku 9 (1566), Shimazu Yoshihisa, Shimazu Yoshihiro, and Shimazu Toshihisa (three siblings who were sons of Shimazu Takahisa – the fifteenth head of the Shimazu clan) attacked Kobayashi Castle during its construction. Shigekata and his younger brother, Mera Norishige, fought valiantly in defense of the castle. With the support of reinforcements from Suki Castle, the defenders killed many Shimazu soldiers. Yoshihiro incurred serious injuries and the Shimazu were forced to retreat. While the Mera retained control of the site, in the wake of the violent clash, only the inner citadel remained.
The Hōshū-Shimazu based in Obi in southern Hyūga were a cadet family of the main branch of the Shimazu of Satsuma Province. In 1568, allied forces of the Hōshū-Shimazu and Hongō clans engaged in a series of clashes against the Hyūga-Itō for control of Obi Castle and its environs. This conflict is known as the Nine Campaigns of Obi and represents the final battle between the Satsuma and Itō clans of Kyūshū. In the aftermath of these battles, Shigekata, serving as a representative of the Itō clan, engaged in negotiations with Hongō Tadaaki who served the Shimazu. This resulted in the withdrawal of the Shimazu army and transfer of the territory in Obi to the Itō. Owing to these results, Shigekata was extolled as an intelligent and courageous bushō. Around this time, he was further awarded Nokubi Castle.
On 5/4 of Genki 3 (1572), Shigekata deployed for the Battle of Kizakibaru. After a failed assault against Kakutō Castle, Shigekata was killed while serving in the rear guard for the fleeing members of the Itō army. Following an inspection by Shimazu Yoshiro of the heads of fallen enemy soldiers, his head was sent to the Ichirin Temple which was the family temple of the Mera family.