Kei Hosogai is a Japanese actor, voice actor, and musician born on October 10, 1984, in Tokyo. He is affiliated with the talent agency GMB Production. Hosogai began his entertainment career in 2008, initially gaining recognition on stage for his role as Hiyoshi Wakashi in the Musical: The Prince of Tennis. He continued to build his career with numerous television, film, and stage productions, including appearances in the Super Sentai series Kaizoku Sentai Gokaiger as Basco Ta Jolokia and the tokusatsu series Ultraman Trigger: New Generation Tiga as Ignis.

As a voice actor, Hosogai is prominently known for his role as Kaoru Hakaze in the Ensemble Stars! multimedia franchise, a project that includes both a mobile game and an anime adaptation. He also voices the character Ikuto Kimijima in The Prince of Tennis II: U-17 World Cup Semifinal. His work in the Ultraman franchise also involves voice performance, as he provides the voice for the character Trigger Dark.

Beyond acting, Hosogai was the bassist for the rock band Cocoa Otoko, which was active from 2010 to 2012 and signed to the Avex Trax label. He is fluent in English, having spent a significant part of his childhood and youth living in the United States, primarily in Seattle, Washington, and Hawaii.