Hiro Yamamoto (山本 紘 Yamamoto Hiro, born April 13, 1961) is an American bassist who was a founding member of grunge band Soundgarden, along with Kim Thayil and Chris Cornell in 1984. He left the band in 1989, and two years later, he started the independent rock band Truly together with Screaming Trees drummer Mark Pickerel and Robert Roth from The Storybook Krooks.
Yamamoto was the founding bassist of Soundgarden. He performed with Cornell, Thayil, and drummer Scott Sundquist on the Deep Six compilation, and performed with Cornell, Thayil, and drummer Matt Cameron on the EPs Screaming Life, Fopp, and Loudest Love, as well as on the albums Ultramega OK and Louder Than Love. His last gig with the band was in 1989 at the Melkweg in Amsterdam, after which Yamamoto left the band following an argument among its members. Jason Everman (formerly of Nirvana) replaced him on the bass briefly, after which Ben Shepherd became the permanent bassist. After Yamamoto departed, he completed the requirements for his master's degree in physical chemistry at Western Washington University.
As did Cornell, Thayil, Cameron, and Shepherd, Yamamoto actively wrote songs for the band:
In 1991, Yamamoto formed a three-piece indie band, Truly; the other members were former Screaming Trees drummer Mark Pickerel and singer Robert Roth. Truly released two studio albums and a compilation of unreleased material before breaking up in 2000. The band reunited in 2008.