[4] Shortly after their vocalist left due to musical differences, they recruited drummer Eiji Kikuchi's older brother Hideaki as lead guitarist.

[4] Yoshii was temporarily providing vocals while they looked for a new singer, but when they received an offer to make a record, he permanently became frontman of the band.

[12] His January 2009 single "Biru Mania" included a cover of "Kuchibiru Motion", which Yoshii wrote for the duo PUFFY two years earlier.

[13] The single "Love & Peace" was released on February 16, 2011, and a cover of "Betsujin" was contributed to the Reichi Nakaido tribute album OK!!!

[18] The January 2015 single "Clear" was his first official release on Triad, which was the debut label of The Yellow Monkey, although his first cover album Yoshii Funk Jr. ~Korega Genten!

", which he composed with lyrics by Yukinojo Mori, is the opening theme song of the Dragon Ball Super anime.

It was released as a single on October 7, 2015, with a B-side cover of "Romantic Ageru yo" that features his former Yellow Monkey bandmate Hideaki Kikuchi on guitar.

[1] On June 26, 2015, it was announced that Yoshii married tarento Kaori Manabe who was pregnant with his child and due to give birth in the fall.

[1] At the end of December 2021, Yoshii visited a specialist after feeling something strange in his throat and was diagnosed with a polyp caused by inflammation.