Chō Motosada served as a bushi during the Azuchi-Momoyama and early Edo periods. Motosada was a retainer of the Mōri clan and served in the Chōshū domain in the Edo period.
Motosada was born as the lineal heir of Chō Motoyoshi. Motoyoshi, was naturalized citizen of Japan originating from the Ming dynasty in China served as a representative of Mōri Terumoto in the central administration of the Mōri family.
On 12/14 of Tenshō 18 (1590), Motosada attended his coming-of-age ceremony and received a certificate for his crowning from Mōri Terumoto. He also received one of the characters from the name of Terumoto, adopting the name of Motosada.
On 7/15 of Keichō 5 (1600), Motosada was granted the official title of Kyūzaemon-no-jō from Terumoto.
In 1600, as an outcome of their defeat in the Battle of Sekigahara, the Mōri were subjected to a reduction of their territory to Suō and Nagato provinces. On 8/27 of Keichō 6 (1601), Motonori’s father, Motoyoshi, was forced to commit seppuku in the Ōshima District of Suō based on an alleged affair with the wet nurse of Mōri Hidenari. The individual with whom Motoyoshi was alleged to have engaged in a relationship strongly denied the allegations, and, after his death, the Chō family was reconstituted during the period that Terumoto remained alive with Motosada serving as the successor to Motoyoshi. Therefore, it is said that there was in fact no illicit relationship, and the allegations were only a pretext to eliminate Motoyoshi.
On 1/17 of Kanei 12 (1635), Motosada received permission from Hidenaru to transfer landholdings of 100 koku to his lineal heir, Chō Narisada, comprising of 50 koku in the village of Iketani in the Saba District of Suō Province and 50 koku in the village of Hishikai in the Ōtsu District of Nagato Province.
On 1/28 of Meireki 3 (1657), Motosada died.