Born in 1662 as the eldest son of Tokugawa Tsunashige, lord of Kofu. He became the 6th shogun in 1709 at age 48 after Tsunayoshi's death. Immediately upon taking office, he abolished Tsunayoshi's infamous Laws of Compassion for Living Things and pardoned over 8,000 prisoners. He appointed the Confucian scholar Arai Hakuseki as his advisor and promoted civilized governance known as the 'Shotoku Reform.' He also undertook fiscal reforms including simplifying Korean embassy receptions and currency recoinage. However, he died of illness after only 3 years in office at age 51. Despite his short reign, he is praised as a wise ruler who swept away the excesses of the Tsunayoshi era.

Gentle, scholarly, and tolerant—he listened carefully to his advisors. Having witnessed Tsunayoshi's extreme policies firsthand, he developed a pragmatic political sensibility.

Though he served only 3 years, he ended the chaos of Tsunayoshi's era by abolishing the Laws of Compassion and appointing Arai Hakuseki, achieving the 'Shotoku Reform.' While not widely known among shoguns, he is increasingly recognized as a hidden wise ruler.