Lifespan: Tenshō 8 (1580) to 5/22 of Genna 9 (1623)
Rank: bushō, daimyō
Title: Junior Fifth Rank (Lower), Lieutenant of Outer Palace Guards of the Left Division, Master of the Imperial Guards of the Left Division
Lord: Toyotomi Hideyoshi → Toyotomi Hideyori → Tokugawa Ieyasu → Tokugawa Hidetada
Domain: Lord of Mino-Kurono, lord of Hōki-Yonago, lord of Iyo-Ōzu
Father: Katō Mitsuyasu
Mother: Daughter of Hitotsuyanagi Naohide
Siblings: Sadayasu, sister (wife of Takenaga Shigekado), Mitsunao
Wife: [Formal] Myōkin-Zenjōni, [Second] Hōganin (daughter of Koide Yoshimasa)
Children: Yasuoki, Naoyasu, daughter (formal wife of Hosokawa Okimasa)
Katō Sadayasu served as a bushō and daimyō during the Azuchi-Momoyama and early Edo periods. In the Edo period, Sadayasu was the lord of the Kurono domain in Mino Province, the lord of Yonago domain in Hōki Province, and the first lord of the Ōzu domain in Iyo Province.
In 1580, Sadayasu was born as the second son of Katō Mitsuyasu, a retainer of Hashiba Hideyoshi (later known as Toyotomi Hideyoshi).
In the eighth month of 1593, his father, Mitsuyasu, died while serving in the Bunroku Campaign on the Korean Peninsula. Sadayasu inherited the headship of the clan at the age of fourteen and entered into service for Hideyoshi with a fief in Kai Province. In 1594, he was conferred the Toyotomi surname. In 1595, Sadayasu was transferred to Kurono in Mino with a fief of 40,000 koku.
In 1600, at the Battle of Sekigahara, Sadayasu initially served Ishida Mitsunari – the leader of the Western Army. He was ordered to defend Inuyama Castle in Owari Province, but he betrayed Mitsunari in favor of the Eastern Army and came under the command of Ii Naomasa. After confronting the Western Army at Ōgaki Castle, at the main Battle of Sekigahara, he fought against the Shimazu army commanded by Shimazu Yoshihiro. After this battle, Sadayasu and Inaba Sadamichi captured Minakuchi-Okayama Castle from Natsuka Masaie. Owing to his valorous service, Tokugawa Ieyasu granted recognition of Sadayasu’s rights to his landholdings.
Sadayasu endeavored to construct Kurono Castle and the town below. In the first month of 1610, he introduced free markets in Kurono. On 7/15, his fief was increased by 20,000 koku and he became the lord of the Yonago domain in Hōki with a fief of 60,000 koku. Beginning in the winter of 1614, he participated on behalf of the Tokugawa in the Siege of Ōsaka, serving meritoriously. In 1617, he was transferred to Iyo Province, becoming the first lord of the Ōzu domain with a fief of 60,000 koku.
On 5/22 of Genna 9 (1623), Sadayasu died at the age of forty-four. He was succeeded by his eldest son, Katō Yasuoki.