Koretada was the eldest son of Morosuke, who held the title of Udaijin (Minister of the Right), and served under Emperor Murakami, and when Emperors Reizei and Enyu, who were the sons of Koretada's younger sister FUJIWARA no Anshi, who held the title of Chugu (Empress), ascended to the throne, he succeeded as well and became Sessho Daijo-daijin (Regent and the Grand Minister), but died early in the following year.
村上天皇のもとの実力者右大臣師輔の長男で、妹の中宮藤原安子が生んだ冷泉天皇、円融天皇が即位すると栄達し、摂政太政大臣にまで上り詰めるが、その翌年に早死にした。