His father's career necessitated moving every few years, resulting in Aku attending three separate junior high schools.
Originally, Yū Aku desired to screenwrite for movies, specifically the then up-and-coming Moonlight Mask series.
Aku started his career in advertisement production, which provided the foundation for his work as a lyricist.
[1] As of 2015, total sales of the singles he has written exceed 68.3 million copies, making him the second best-selling lyricist in Japan behind only Yasushi Akimoto.
[2] In 1977, he wrote the lyrics to The TV Asahi Song for the occasion of the television channel's most recent name change.