Who was Metallica's bassist before Cliff Burton joined?

The bassist in Metallica before Cliff Burton joined was Ron McGovney. He played with the band during its formative Los Angeles period, from October 1981 until December 1982, making him Metallica’s original bassist.

McGovney already knew James Hetfield from the garage band Leather Charm. After Hetfield and Lars Ulrich formed Metallica in October 1981, McGovney joined the early lineup alongside guitarist Dave Mustaine. He appeared on early demos, including recordings connected with “Hit the Lights,” before the band had made its debut album.

McGovney left Metallica on December 10, 1982, after tensions within the group. Cliff Burton replaced him soon afterward, bringing a more developed musical approach and becoming a key creative force on the next three albums.

A frequent mistake is naming Jason Newsted or Robert Trujillo, both of whom joined Metallica much later. Newsted replaced Burton in 1986, while Trujillo became bassist in 2003. Bob Rock played bass on parts of one later album but was never Metallica’s pre-Burton bassist.