(born January 25, 1994, in Tokyo), better known professionally as Hiro, is a Japanese singer and the lead vocalist of the Japanese rock band My First Story.
Hiro was born on January 25, 1994, the youngest son of Japanese singers Masako Mori and Shinichi Mori. He has two elder brothers, the eldest of whom is Takahiro Moriuchi, the lead singer of the band One Ok Rock and Tomohiro Moriuchi who works on TV Tokyo. In April 2005, his parents divorced when he was 11. Following the divorce, he and his older brother, Tomohiro, resided with their father; their mother took custody of their oldest brother, Takahiro.
Hiro announced his marriage to actress and model Maika Yamamoto on October 13, 2024, through a post in his official social media account.
Hiro signed with Johnny's Entertainment on December 1, 2002, when he was 8 years old. He was the youngest Johnny's Jr. and remained active until 2005.
He is currently active as the lead vocalist of the Japanese rock band, My First Story, which was formed in Shibuya in 2011. He released his solo debut album Sing;est on January 20, 2021, through Universal Music Japan. It contains ten covers of songs originally performed by exclusively female vocalists.