Supporting Hisamitsu, he got involved in politics in Kyoto, planning the reconciliation between the imperial court and the Shogunate with Tomomi IWAKURA, and promoting the assumption of Shogun-guardian post by Yoshinobu TOKUGAWA and the post of office of the president of political affairs by Yoshinaga MATSUDAIRA (the lord of Fukui Domain).
久光を擁立して京都の政局に関わり、公家の岩倉具視らと公武合体政策を画策し、徳川慶喜の将軍後見職、福井藩主松平慶永の政事総裁職就任などを進めた。