Hiroki Konishi is the birth name of the Japanese actor and voice actor professionally known as Ryosei Konishi. He was born on February 20, 1982, in Tokyo, Japan. He began his entertainment career in 2003 and used his birth name as his stage name until January 2007, when he formally adopted the name Ryosei Konishi.

Konishi's career as a voice actor includes several notable anime television roles in the mid-2000s. His debut voice acting role was in the 2004 anime series School Rumble, where he provided the voice for the character Oji Karasuma. In 2005, he voiced the character Pierre in the magical girl anime Sugar Sugar Rune. The following year, in 2006, he took on the voice role of the character 3-5-10, also known as Sa-go-juu, in the anime series G-9. This original video animation, directed by Keita Amemiya and produced by Toei Animation, was released on September 27, 2006.

While his voice acting work is a part of his portfolio, Hiroki Konishi's primary career focus is live-action performance. He is best known for his leading role as Kouga Saejima, the titular character in the tokusatsu series GARO, which he played from 2005 to 2006 and in subsequent films and sequels. A significant portion of his career is also dedicated to theatre and musicals, with prominent roles in productions such as Les Misérables as Marius, The Light in the Piazza, and the musical adaptation of The Prince of Tennis. His voice acting credits are limited to the mid-2000s, with no major anime roles recorded after the School Rumble OVA released in 2008.