Sōichirō Hoshi is a veteran Japanese voice actor and singer born on May 30, 1972, in Aizuwakamatsu, Fukushima Prefecture. He has been active in the industry since 1993 and is affiliated with the talent agency Arts Vision. His decision to become a voice actor was inspired by watching the Studio Ghibli film Kiki's Delivery Service during his high school years. To pursue this goal, he enrolled in the Tokyo Announce Gakuin and later graduated from the ninth special class of the Japan Narration Acting Institute.

Hoshi's career began with minor roles in the mid-1990s, with his first anime appearance as Senzō Tachibana in Nintama Rantarō. His breakthrough came in the year 2000 when he was cast as the energetic Son Goku in the anime adaptation of Saiyuki. This role was followed by his portrayal of Kira Yamato in the immensely popular Mobile Suit Gundam Seed in 2002, a performance that solidified his status as a leading voice actor and became one of his most iconic and enduring roles. He has since reprised the role of Kira Yamato in numerous sequels, specials, and the 2024 theatrical film Mobile Suit Gundam Seed Freedom.

Throughout his extensive career, Hoshi has demonstrated considerable versatility, voicing a wide array of characters. He is known for his youthful and soft-spoken heroes, as well as for convincingly portraying hot-blooded, energetic characters, and even morally ambiguous or villainous roles. This range is evident in his many prominent roles, which include the cheerful and determined Keiichi Maebara in the Higurashi: When They Cry series, the flamboyant Kazuki Fuuchouin in GetBackers, the perverted protagonist Tomoki Sakurai in Heaven's Lost Property, the hot-blooded Masaru Daimon in Digimon Savers, and the enigmatic Brera Sterne in Macross Frontier. He has also taken on villainous parts such as Death Gun in Sword Art Online and Goro Akechi in Persona 5.

In video games, Hoshi is known for voicing Sanada Yukimura in the Sengoku Basara series, Kilik in the Soulcalibur series, and various characters in the long-running Harukanaru Toki no Naka de franchise. His work also extends to tokusatsu, where he provided the voice for Birca in Engine Sentai Go-onger.

Hoshi has been recognized for his contributions to the industry with several awards. He won the voice acting award at the Anime Grand Prix for two consecutive years, in 2005 and 2006, for his performances in Mobile Suit Gundam Seed. He was also a nominee for Best Actor in a Supporting Role at the 1st Seiyu Awards for the same role. In 2025, he received the Kei Tomiyama Award at the 19th Seiyu Awards.

For work in adult-oriented games and projects, Hoshi uses the pseudonym Takeshi Aiba. He is also a singer and has been part of music units related to his various franchises, such as Re:vale for the IDOLiSH7 project. His voice is distinctive, and he is known for his frequent collaborations with director Goro Taniguchi and fellow voice actors like Akira Ishida and Kenichi Suzumura.