He was considered a child prodigy, and his father, Sasaki Hirotsuna, taught him the basics of poetry composition and encouraged him to memorize classical tanka verses.

In 1894 Sasaki published a lengthy patriotic poem Shina seibatsu no Uta (“The Song of the Conquest of China”), on the occasion of the start of the First Sino-Japanese War.

He eventually published an additional eleven collections of tanka, which included Shingetsu (“New Moon”, 1912), Toyohata gumo (“Clouds Streaming in the Wind”, 1929), and Yama to mizu to (“Mountains and Water”, 1951).

In recognition of these efforts, Sasaki was offered the post of lecturer at Tokyo Imperial University in 1905, and was officially commissioned by the Ministry of Education to work on a modern commentary to the Man'yōshū .

Sasaki worked together with his father on these efforts, and published a comprehensive survey of medieval waka (Wakashi no kenkyu, “Studies in Japanese Poetry”, 1915).