Jason Newsted played bass on Metallica's self-titled 1991 album, known as The Black Album.
Newsted joined Metallica after the death of bassist Cliff Burton in 1986. His first full-length Metallica studio album was ...And Justice for All, although his bass contribution on that record was famously mixed very quietly. The Black Album gave the bass a much more audible and important role.
Bob Rock encouraged the band to strengthen the low end, and Newsted's playing became a more noticeable part of the finished sound. He is credited with bass on the album, alongside James Hetfield on guitars and vocals, Lars Ulrich on drums, and Kirk Hammett on lead guitar.
Newsted remained Metallica's bassist until leaving the band in 2001. Robert Trujillo later became the group's bassist, but he did not play on The Black Album. This distinction is useful because Trujillo appears in later Metallica history while Newsted is the bassist connected to the 1991 recording.