In 765 he was promoted to ju go-i no jō (従五位上) and division chief (督) of the imperial guard, and changed his name from Kuromaro to Korekimi.

Shortly after Kanmu's ascension to the throne in 781, a number of important officials since Kōnin's time, including sadaijin Fujiwara no Uona, udaijin Ōnakatomi no Kiyomaro, dainagon Isonokami no Yakatsugu, and udaijin Fujiwara no Tamaro, died or left office, and Korekimi was again rapidly promoted.

In 781 he was promoted to shō san-mi (正三位) and chūnagon, in 782 to dainagon, and in 783 to udaijin, making him the most powerful man in the daijō-kan. Korekimi died in 789, at the age of 63.

His rank at the time of his death was ju ni-i (従二位), and he held positions both as udaijin and as a general in the imperial guard.

He was a capable official, well versed in the governmental affairs of the day, who made decisions quickly and without delay.