Itagaki grew up in Kanazawa Ward, Yokohama City, Japan.
He graduated from Kanagawa Prefectural Hitorizawa High School and the Tokyo College of Music.
He studied trombone under the direction of former NHK Symphony Orchestra trombonist Kiyoshi Itou and former Japan Philharmonic Orchestra trombonist the late Naoyuki Shiraishi. He also studied piano under the direction of Kuniko Sugiyama and Taeko Itou.
He placed third overall and first in wind instruments in the 34th Kitakyuushu Art Festival Music Competition.
Currently, he is a freelance musician who assists in orchestras, solo recitals, and chamber music recitals. He is also the president of the MUSICA PORTO mixed ensemble.
Regarding his experience as a wind ensemble conductor, he has instructed his high school alma matter's wind ensemble club since 1989, which has gone on to place sixth (with a one-point difference in third place) in the 2001 Eastern Japan division of the All-Japan Band Competition.
In addition, he has served as an advisor and conductor for the wind ensemble clubs at Chiba Prefectural Naritakita High School, Chiba Prefectural Isobe High School, Iwate Prefectural Tohno High School, and Iwate Prefectural Kamaishiminami High School.
In addition to conducting our group, he was a permanent conductor of the Kanazawa Wind Ensemble from 1994 to 2000. He has educated a wide range of generations in music, from elementary school students to adult amateurs, and has cultivated their musical skills, resulting in high praise throughout his musical career.