He struggled until finding major success in the mid-1980s, when he started singing theme songs for anime and tokusatsu television shows.

[3] Lazy reunited in 1997, and Kageyama briefly worked with Masaaki Endoh as the duo Metal Brothers before they formed the anison supergroup JAM Project in 2000 with several other vocalists.

While still a high school student in Osaka, Kageyama formed the rock band Lazy with classmates Akira Takasaki and Shunji Inoue at age 16.

He would later describe the period after leaving Lazy as the hardest of his career, "I just couldn't find a good groove, and the crowd numbers at my gigs started to dwindle.

"[4] Kageyama was part of a special team at Columbia called Project Monolith, which focused on music for Dragon Ball Z.

It included himself, Shinichi Ishihara, Kuko (now known as "Ikuko") and Yuka as singers, Chiho Kiyooka and Hideki Matsutake as composers, and Sakiko Iwamuro and Dai Satō as lyricists.

In 2000, he signed with Lantis, then run by his Lazy bandmate Inoue, and co-founded the anison supergroup JAM Project with Endoh and Ichiro Mizuki.

[9] Kageyama is also the voice of Zaruba, a mystical talking ring, as well as the loyal ally and advisor to the titular hero of the tokusatsu franchise Garo, for which JAM Project has performed the opening themes.