Yukio Yamagata is a Japanese singer, actor, and voice actor born on March 11, 1957, in Fukuoka Prefecture, Japan. Before establishing his career in voice work and tokusatsu productions, Yamagata was a member of a soul band called LOVE and performed on United States military bases in Japan. He later became a member of the band Tush, through which he performed theme songs for anime series such as Yattodetaman. His stage career has included prominent roles in major musical productions, including Thuy in Miss Saigon and Thénardier in Les Misérables.

Yamagata is widely recognized for his contributions to the Super Sentai franchise, both as a vocalist and as a voice actor. He is best known for performing the opening theme song "Gaoranger Hoero!!" for Hyakujuu Sentai Gaoranger, and has also sung theme songs for the anime Baxinger and the ending theme for Braiger. His voice acting roles in the tokusatsu genre include voicing the Hades Org in Hyakujuu Sentai Gaoranger The Movie and providing the voice for Shishi-oh (Lion Haoh) in Shuriken Sentai Ninninger. Additionally, he voiced the character Kaneto Muraki in the 1987 anime adaptation of Digital Devil Story: Megami Tensei.

In the self-parody series Unofficial Sentai Akibaranger, Yamagata made a notable appearance playing a fictionalized version of himself. In season one, episode nine, he appears as himself, initially presented as a mysterious figure named Yamagin before revealing his identity to the main characters. He reprised this self-referential role in season two, episode three, again appearing as an illusionary version of himself. Beyond this acting appearance, his voice is a prominent part of the series' musical identity. He is featured on the first season's opening theme "Unofficial Sentai Akibaranger" performed by Haruko Momoi featuring Yukio Yamagata, and also performed on the ending theme "Super Sentai Hikōnin Ōenka" alongside Masato Wada and Mojo. For the second season, he collaborated again with Haruko Momoi and Mojo on the opening theme "Akibaranger Season Tsuu!".

Yamagata is known for his distinctive rough, husky vocal quality, which he has stated was developed and refined during his time as a soul singer, often attributing the character of his voice to drinking bourbon during that period of his career. Over the decades, he has performed theme songs and insert songs for numerous series, including Denji Sentai Megaranger, Mirai Sentai Timeranger, Tokumei Sentai Go-Busters, Ressha Sentai ToQger, Doubutsu Sentai Zyuohger, and Kikai Sentai Zenkaiger. In 2009, he performed internationally at the Anime Friends convention in Brazil, and he is known to be a close friend of fellow anison singer Isao Taira.