Toshiyuki Toyonaga is a Japanese actor, voice actor, and singer born on April 28, 1984, in Hachiōji, Tokyo. He began his entertainment career as a child actor at the age of ten, making his debut in a stage musical in 1995 and subsequently working in both television and stage productions. He made his debut as a voice actor in 2002, with his first role being Takahiro in the original video animation (OVA) Yokohama Kaidashi Kikou: Quiet Country Cafe. He is currently affiliated with the agency Super Eccentric Theater Inc..

Toyonaga has built an extensive and diverse portfolio of voice roles in anime, often portraying young male characters with a wide emotional range. One of his earliest prominent roles was as Mikado Ryūgamine in the long-running and popular series Durarara!!, a character that helped raise his profile in the industry. His filmography includes a vast array of characters across many genres. He has voiced Shun Matsuoka in You and Me., Hideyoshi Nagachika in Tokyo Ghoul, Mahiro Fuwa in Blast of Tempest, and Yūki Tenpōin in Code:Breaker. In the sports anime genre, he is known for roles such as Kenjirō Shirabu in Haikyu!!, Haiji Kiyose in Run with the Wind, and Asahi Shiina in the Free! series. He also voiced the protagonist Yuri Katsuki in the acclaimed figure skating anime Yuri on Ice.

In addition to his work in anime, Toyonaga is also a singer and songwriter. He released his first album, "Music of the Entertainment," in 2014 and made his major-label debut with the single "Reason" later that same year, which was used as the theme song for the PlayStation Vita game Durarara!! Relay. He has composed and written songs for various projects and has even written pieces for his fellow voice actors, including a song titled "Flower" for Kana Hanazawa.

His contributions to voice acting have been recognized with significant industry awards. In 2018, he won the Best Lead Actor award at the 12th Seiyu Awards for his performances, which included his acclaimed role in Yuri on Ice.

Throughout his career, Toyonaga has frequently collaborated with many other voice actors across multiple projects, forming lasting professional relationships. He has worked alongside Nobunaga Shimazaki in series such as Free! and Yuri on Ice, and with Kouki Uchiyama in shows like Blast of Tempest, Yuri on Ice, Free!, and Buddy Daddies. He is also known to be close friends with fellow voice actor Ryohei Kimura, with whom he has co-starred in numerous works.