However, Ienari continued to wield much power from behind the throne, and it was not until after his death in 1841 that Senior Rōjū Mizuno Tadakuni was able to purge the government of his clique, and to implement measures to overhaul the shogunate's finances and controls in the aftermath of the Great Tenpō Famine of 1832–36.

Known as the Tenpō Reforms, these numerous sumptuary laws attempted to stabilize the economy through a return to the frugality, simplicity and discipline that were characteristic of the early Edo period, by banning most forms of entertainment and displays of wealth.

Increasing criticism of the government's handling of foreign affairs led to the Bansha no goku in 1839, suppressing rangaku studies.

Another part of the Reform included the Agechi-rei of 1843, which was to have daimyō in the vicinity of Edo and Ōsaka surrender their holdings for equal amounts of land elsewhere, thereby consolidating Tokugawa control over these strategically vital areas.

Ieyoshi died on 27 July 1853, before the treaty could be concluded, of heart failure possibly brought on by heat stroke, and was succeeded by his third son Tokugawa Iesada.