His birth name was Matsudaira Shichirōmaro (松平七郎麻呂)[1] His mother, Princess Arisugawa Yoshiko, was a member of the Arisugawa-no-miya, a cadet branch of the imperial family; through her, he was a third cousin (once removed) of the then-Emperor Ninkō.

[3] At the instigation of his father, Shichirōmaro was adopted by the Hitotsubashi-Tokugawa family in order to have a better chance of succeeding to the shogunate[4] and changed his first name to Akimune (昭致).

[11] The three men then took numerous steps to quell political unrest in the Kyoto area, and gathered allies to counter the activities of the rebellious Chōshū Domain.

Fearing the renewed strengthening of the Tokugawa shogunate under a strong and wise ruler, samurai from Satsuma, Chōshū and Tosa formed an alliance to counter it.

coupled with a fear of the new shōgun as the "Rebirth of Ieyasu" (家康の再来) who would continue to usurp the power of the Emperor, they worked to bring about an end to the shogunate, though they varied in their approaches.

In particular, Tosa was more moderate; it proposed a compromise whereby Yoshinobu would resign as shōgun, but preside over a new national governing council composed of various daimyōs.

To this end, Yamanouchi Toyonori, the lord of Tosa, together with his advisor, Gotō Shōjirō, petitioned Yoshinobu to resign in order to make this possible.

[18] They secretly obtained an imperial edict[18] calling for the use of force against Yoshinobu (later shown to be a forgery)[20] and moved a massive number of Satsuma and Chōshū troops into Kyoto.

[24] When the Tokugawa forces arrived outside Kyoto, they were refused entry, and were attacked by Satsuma and Chōshū troops, starting the Battle of Toba–Fushimi, the first clash of the Boshin War.

The close relationship between father and son is highlighted in the illustrated biography on Prince Tokugawa Iesato titled The Art of Peace.

[32] Living a life in quiet retirement, Yoshinobu indulged in many hobbies, including oil painting, kyudo (archery), hunting, photography, and cycling.

[34] His other great-grandson, Yasuhisa Tokugawa of the Mito line, is the former Chief Priest at Yasukuni Shrine and current Kaicho of the Kokusai Budoin (IMAF).

On 3 June 1902, the Emperor Meiji allowed him to re-establish his own house as a Tokugawa branch (bekke) with the highest rank in the peerage, that of prince (kōshaku), for his loyal service to Japan.

[citation needed] On 12 July 1943, he was killed in action during World War II when the submarine Ro-101 he was deployed on was fired on by the destroyer USS Taylor in Indispensable Strait near Guadalcanal in the Solomon Islands.