Ikai Nobusada served as a bushō during the Sengoku and Azuchi-Momoyama periods. He is also known as Sadahisa and Masakatsu, but his signature is in the name of Nobusada. His surname is also known as Ikaino.
Nobusada was born as the son of Ikaino Sado-no-kami Nobuhisa.
Nobusada served as the head of the naval forces based in Katata in the Shiga District of Ōmi Province. First, he served the Rokkaku clan, and, later, associated with the Azai clan. In 1570, after the end of the Siege of Shiga, Nobusada, along with others from Katata including Isome Matajirō and Baba Magojirō, surrendered to Oda Nobunaga. Thereafter, he was assigned to keep watch on the Azai clan. On 11/25 of Genki 1 (1570), Nobusada joined with Sakai Masahisa (dispatched by the Oda) to defend Katata as a means to suppress the distribution of provisions. However, in an attack by forces led by Maeba Kagemasa of the Asakura army, Masahisa was killed while Nobusada fled.
Later, Nobunaga granted the Shiga District to Nobusada and he served under the command of Akechi Mitsuhide. In addition to the Shiga District, Nobusada also controlled marine transport and fishing rights on Lake Biwa. Acting with a degree of independence in his territory, Nobusada also served, along with Kutsuki Mototsuna, as governors of the Takashima District under the direct jurisdiction of Nobunaga.
In the seventh month of 1572, Nobusada participated as a member of the Akechi forces to burn and shoot at coastline bases of the Azai clan.
Nobusada’s name last appears on a receipt for rice in relation to hunting grounds dated 4/22 of Tenshō 10 (1582). Given the absence of any traces thereafter, it is surmised that he was killed while fighting on behalf of the Akechi forces in the Honnō Temple Incident – the coup d’état orchestrated by Akechi Mitsuhide that resulted in the unexpected death of Oda Nobunaga on 6/2 of Tenshō 10 (1582).
Nobusada’s son, Hidesada, also served Mitsuhide, receiving the name of Akechi Hanzaemon Hidesada, but, on the occasion of the Honnō Temple Incident, he parted ways with his father, and apprehended Saitō Toshimitsu, who was in hiding in Ōmi. Thereafter, after serving as a retainer of Niwa Nagahide, he served Tokugawa Ieyasu and was awarded a fief of 490 koku in Tōtōmi and Suruga provinces.