His grandfather, FUJIWARA no Morosuke, was an influential figure who supported Emperor Murakami's reign as Udaijin (Minister of the Right), and when his daughter, Empress FUJIWARA no Anshi/Yasuiko, gave birth to Emperor Reizei and Emperor Enyu he strengthened his position as a maternal relative of the Imperial Family.
祖父の藤原師輔は村上天皇の治世を右大臣として支えた実力者で、娘の中宮藤原安子が後の冷泉天皇、円融天皇を生んだことで外戚として立場を強化した。