When Emperor Junna (the third prince of Emperor Kanmu whose mother was FUJIWARA no Tabiko, a daughter of Momokawa) was enthroned in 823, Momokawa was given Shoichii Daijo-daijin (Grand Minister with Senior First Rank) as the maternal grandfather of the Emperor.
弘仁14年（823年）淳和天皇（桓武天皇第三皇子　母は百川の子・藤原旅子）即位に伴い、外祖父として正一位太政大臣を追贈される。