Yoshihiro Hanaoka entered the College of Liberal Arts, Division of Humanities (then) of ICU in April 1998, having been attracted to the wide variety of disciplines it offers including music. While studying fine arts, music, literature, psychology, and other subjects, he reaffirmed his resolve to pursue a career in music. After leaving ICU, he went on to study at Mannes College of Music in New York in 2003. During his time at Mannes, he served as a rehearsal conductor of Cantori New York and the New York Men's Choir. He was the choral inspector for Mahler's second symphony, "Resurrection," performed at the concert held in honor of United Nations Secretary-General Ban Ki-moon at the UN headquarters in 2007.

In the same year, he completed the master's program in choral conducting. After returning to Japan, he conducted the Philharmonic Chorus of Tokyo in 2008 and 2009. In 2008, he covered Kenji Otani to direct the Taipei Philharmonic Youth Choir as a guest conductor, introducing Japanese and American works to the Taiwanese audience to their great satisfaction. In 2017, he performed Haydn's "The Creation" with the ICU OGC Chorus and the Professionals Orchestra. He won the Mykola Sukach Award for the best conductor at the master class in conducting hosted by the Chernihiv Philharmony in Ukraine in 2019.

Now, he serves not only as a conductor for more than 10 organizations but also as the jury of numerous competitions held across Japan, including the Nagano Bloc round of the NHK All-Japan School Choir Competition and the Nagano round of JCA National Choral Competition. He is also active in teaching school choirs ranging from elementary to high school levels.

He studied conducting with Kenji Otani, Mark Shapiro, Daisuke Nagamine, Heiichiro Oyama, Mitsunobu Takaya, and Mykola Vasyliovych Sukach, and music history and theory with Professor Emeritus Masakata Kanazawa and Professor Emeritus Tatsuhiko Itoh of ICU.