Gakuji Arao graduated with a master's degree from Tokyo University of the Arts. He studied composition under Masayuki Nagatomi, Yoriaki Matsudaira and Ichiro Nodaira. He was also a piano student of Mayumi Nozawa and Ikuko Endo.

Arao is a piano accompanist widely trusted by instrumental and vocal musicians. Among them, he has been playing as a member of Yasuo Watani Harmonica Trio since 2009.

He is currently an associate professor at Tokyo College of Music and a member of the board of directors of Solfege Studies Conference Japan.