After taking office as Roju, he negotiated with the Imperial court over the opening of Hyogo Port and in the meantime, he was ordered to be in charge of taking care of Edo, together with one of the Gosanke (three privileged branches of Tokugawa family) members, Yoshiatsu TOKUGAWA and Tadashige MATSUDAIRA (the lord of Oshi Domain in Musashi Province) of the Oshi Domain, while Iemochi was to go to Kyoto at the end of the year.
老中就任後は兵庫開港をめぐって朝廷対策に奔走する一方、年末に家茂の上洛が決定すると、御三家の徳川慶篤、忍藩侯の松平忠誠(武蔵国忍藩主)とともに江戸留守居役を命じられる。