Born into the Tayasu branch of the Tokugawa family, he became lord of Fukui Domain at age eleven. He recruited outstanding retainers and scholars—Hashimoto Sanai and Yokoi Shonan chief among them—to drive domain reform. His enlightened outlook and political skill earned him recognition alongside Shimazu Nariakira, Yamauchi Yodo, and Date Munenari as one of the 'Four Wise Lords of the Bakumatsu.' His advocacy for Hitotsubashi Yoshinobu in the shogunal succession dispute brought him into sharp conflict with Tairo Ii Naosuke, who ordered him into retirement during the Ansei Purge of 1858. After Ii's assassination he returned to politics as Chief of Political Affairs, pushing shogunate reform under the principle of unity between court and shogunate. He actively supported the return of political power to the emperor and was appointed to the new Meiji government's council after the Restoration, participating in laying the new state's foundations. During his tenure in Fukui he encouraged domain retainers to acquire Western technology and promoted the introduction of Western-style armaments and industrial development. Known for his enthusiasm for Western culture ('Dutch mania'), he was also a cultured daimyo who died in 1890 at sixty-two.

Open-minded and flexible, he recruited talented people regardless of status. As a moderate reformer, he excelled at mediating between opposing factions and was widely respected.

Promoted modernization of Fukui Domain and served as a key mediator in Bakumatsu politics. His ability to identify talent like Hashimoto Sanai and Yokoi Shonan is highly regarded.