Sakai Masahisa served as a bushō during the Sengoku and Azuchi-Momoyama periods. He was a retainer of the Oda clan.
There are assorted theories concerning his origins. One is that he came from the village of Gakuden in the Niwa District of Owari Province, and, according to another, he is identified as Sakai Ukon of Mino Province. His relationship to Sakai Taizen (the chief retainer of the Kiyosu-Oda clan) who appears in the authenticated biography of Oda Nobunaga known as the Shinchō-kōki is uncertain, but several individuals with the same surname served as retainers of the Oda family so Masahisa is surmised to be of the same family.
According to one source, he first served the Saitō clan of Mino Province, then later served Oda Nobunaga. The period when he began to serve Nobunaga is unclear, but, in the Shinchō-kōki, when Iwanari Tomomichi was attacked during the Siege of Shōryūji Castle south of Kyōto in Yamashiro on 9/28 of Eiroku 11 (1568), Masahisa’s name first appears (along with Shibata Katsuie, Mori Yoshinari, and Hachiya Yoritaka) as one of the generals of the Oda forces. After Nobunaga marched to Kyōto, Masahisa participated in the attack on Shōryūji and, together with Katsuie and the others, garnered over fifty heads. Thereafter, these four generals were joined by Sakuma Nobumori to engage in civil affairs in the capital and the Kinai region including the implementation of various prohibitions and levying of taxes.
In 1569, Masahisa participated in the invasion of Ise Province by Nobunaga. At the Siege of Ōkawachi Castle, his name appears as one of the generals.
On 6/21 of Genki 1 (1570), Nobunaga attacked Azai Nagamasa of Kōhoku. In this event, Masahisa attacked into the foothills of Mount Odani and burned the town below Odani Castle. On 6/28, Asakura Yoshikage sought to counter Nobunaga’s attack on Odani by dispatching reinforcements, leading to the Battle of Anegawa. Masahisa served in the vanguard in this battle, but the Sakai division incurred serious losses and, owing to tactical errors, Masahisa’s eldest son, Sakai Hisatsune, was killed in action.
As a vindication of his honor, Masahisa joined the Siege of Shiga in Ōmi Province that began on 9/16, but this turned into an encirclement of Mount Hiei, lasting a very long time. On 11/25, as the end of this extended conflict approached, Ikai Nobusada of Katata (the northern part of Ōtsu) surrendered so, together with Andō Uemon-no-suke and Kuwabara Heibei, Masahisa attempted to occupy Katata. At this moment, Masahisa was subject to a counterattack by Maeba Kagemasa and others from the Asakura army who had been holed-up on Mount Hiei. Isolated, he clashed with Kagemasa and both men were killed in action. According to the Shinchō-kōki, Masahisa fought with renowned passion.
After his death, Masahisa was succeeded by his second son, Etchū-no-kami (his real name is unknown). Etchū-no-kami, however, died in the Honnō Temple Incident as a martyr of Oda Nobutada and the family was not carried on by Masahisa’s descendants.