Daichi Yamaguchi is a Japanese actor and voice talent born on April 21, 1988, in Kagoshima Prefecture, Japan. He is affiliated with the talent agency BLUE LABEL. Standing at 172 centimeters and weighing 58 kilograms with blood type A, Yamaguchi began his entertainment career in 2011, making his acting debut in the television drama series Ore no Sora Keiji-hen. His professional skill set includes action performance and cooking, while his hobbies include hip-hop dance, strength training, and pursuing a healthy lifestyle.

While primarily known as a live-action actor, Yamaguchi has contributed to anime voice acting. His most recognized voice role is Ikazuchi in the series Kamen Rider Zero-One Short Anime Everyone's Daily Life, an animated short released in 2020. He is also known for portraying the live-action versions of the same character. In the Kamen Rider Zero-One franchise, he plays the recurring role of Space Rascal Raiden, who transforms into Kamen Rider Ikazuchi. He previously appeared in the series Rider Time Kamen Rider Ryuji as Kimura. His filmography within the franchise includes the film Zero-One Others Kamen Rider MetsubouJinrai.

Beyond Kamen Rider, Yamaguchi has an extensive career in live-action television and theater. His television credits include roles in dramas such as Kaseifu no Mitazono Season 5, 13-sai no Hello Work, TEAM Keishicho Tokubetsu Hanzai Soshiki, GTO, Totsuzen Desu ga, Ashita Kekkon Shimasu, Shukatsu Kazoku, and 37-sai de Isha ni Natta Boku.

On stage, he has performed in major theatrical productions, including Fate/Grand Order THE STAGE: Sacred Round Table Domain Camelot, the stage adaptation of Warriors Orochi, Kamen Teacher, Sengoku BASARA vs Devil May Cry, and Claudo to Issho ni. Despite multiple past auditions for Kamen Rider and Super Sentai roles, he continued to pursue these opportunities and successfully secured his roles in the franchise.