Early in his tenure, he revived the practice of borrowing money from his retainers, which he used to fund the military modernization of the domain in response to ever increasing demands from the shogunate to contribute to Japan's coastal defenses.
In 1863, he was ordered to accompany Shogun Tokugawa Iemochi to Kyoto and was placed in charge of security at Nijō Castle during the visit.
Politically Uesugi Narinori was a reformer, and supported ending Japan's national isolation policy.
With the start of the Boshin War, Uesugi Narinori was initially inclined to support the new Meiji government; however Yonezawa Domain was targeted for destruction by the Satchō Alliance along with Aizu Domain and his letters to the new government were rebuffed with exceeding rude responses.
However, with the defection of Shibata Domain, the tide turned and the Uesugi forces were pushed back.