In 1858 he had audience with shōgun Iesada and his wife, Atsuhime short after he was adopted as their son and named as the successor to the main Tokugawa house.

Before Iesada died he give his will to Ii Naosuke, that: As part of the kōbu gattai ("Union of Court and Bakufu") movement, On 11 February 1862, Iemochi married Princess Kazu, daughter of Emperor Ninko.

On 22 April 1863 (Bunkyū 3, 5th day of the 3rd month), shōgun Iemochi traveled in a great procession to the capital.

[2] His early death at the age of 20 put an end to his short marriage with princess Kazu-no-Miya.

At that time Tayasu Kamenosuke was only 3 years old, but as the Tokugawa shogunate was at war with Chōshū, the adult Yoshinobu was appointed the fifteenth shōgun.