[3] He was the son of a wealthy farming family from Tōno, Iwate.
In 1908, he became acquainted with Kunio Yanagita, and Sasaki began to collaborate with Yanagita on collecting the oral traditions and tales of Iwate Prefecture.
In his later years, he became friends with the poet Kenji Miyazawa with whom he shared his discoveries.
Sasaki suffered from respiratory problems and died at the age of 46.
Professionally, Sasaki published a number of books of collected folktales and customs.