Nagako Fujiwara was born around 1100. Sanuki-no-Tenji or Sanukino-Suke being her name as a Court lady. The name derived from the post of her father, Akitsuna, who was Lord of Sanuki Province (Kagawa Prefecture).
When Emperor Horikawa was seriously ill (1101), she nursed him and was granted clothes upon his recovery. She then served Emperor Gotoba and was trusted deeply by ex-Emperor Toba even after she resigned. She became mentally deranged around 1118. Her diary Sanuki-no-Tenji Nikki is noted.