Hetfield and Lars Ulrich came from different worlds to form Metallica in the L.A. suburbs in 1981. Hetfield, whose father was owner of a trucking company and mother a light-opera singer, was raised in a strict Christian Science home; Ulrich, a recently transplanted Dane, had intended to become a professional tennis player like his father, Torben Ulrich. What the two teenagers shared was an interest in the gritty music of U.K. hard rockers Motörhead. Adding guitarist Dave Mustaine and bassist Ron McGovney, the band started writing songs and recording demo tapes. Metallica's lineup solidified after Clifford Lee Burton replaced McGovney in 1982, and the Bay Area guitarist Kirk Hammett replaced Mustaine the following year. Mustaine, who was booted out for excessive substance abuse, went on to form Megadeth.

After gaining a solid cult following among fans who could not identify with contemporary pretty-boy pop-metal combos such as Van Halen and Bon Jovi, Metallica became known for their sophisticated, often complex song structures and serious lyrics that reflected teen obsessions with anger, despair, fear and death. In sharp contrast to those of other death-obsessed metal bands, Metallica's lyrics pose deeper questions about justice and retribution, drug addiction, mental illness and political violence. The group's debut album, Kill 'Em All, is an anarchic catharsis of gloom, with songs like "No Remorse" decrying the insanity of war and "Seek and Destroy" looking at mindless street violence. (Rereleased in 1986, the album went to Number 155.) On subsequent albums, the subject matter alternated between the political (...And Justice for All) and the personal (Metallica).

In 1986 Metallica's tour bus skidded off an icy road in Sweden, killing bassist Burton. The surviving members took some time off before regrouping with ex–Flotsam and Jetsam bassist Jason Newsted. Newsted's more solid playing style brought a thicker, tighter sound, which contributed to the group's massive success in the late '80s and early '90s. On August 8th, 1992, the band experienced another near-tragedy when their pyrotechnics went awry during an ill-fated performance with Guns n' Roses (it was the same night of G n' R's notorious riot show) at Montreal's Olympic Stadium; Hetfield wound up walking into a wall of flames and suffering serious burns, but recovered fully.

Metallica had developed their following without the benefit of radio play, so it came as a bit of a surprise when Master of Puppets reached Number 29 in 1986. The follow-up EP, Garage Days Re-Revisited, a collection of covers of songs by various punk and metal bands including Killing Joke and the Misfits, made it to Number 28. Metallica's first Top 10 album was ...And Justice for All, which reached Number Six in 1988 with its single "One," breaking in to the Top 40 at Number 35. Its striking video included clips from the 1971 antiwar film adaptation of Dalton Trumbo's Johnny Got His Gun, the tale of a faceless quadruple-amputee World War I veteran. After a three-year hiatus, the much-anticipated Metallica (a.k.a. the Black Album) entered the charts at Number One. The album contained a string of hits, including "Enter Sandman" (Number 16), "The Unforgiven" (Number 35) and "Nothing Else Matters" (Number 34). Metallica's first official live album, Live Shit (Number 26, 1993), was recorded in 1993 over five shows in Mexico City.

In 1994 Metallica sued their longtime label, Elektra, seeking escape from a contract that locked the band in to a modest 14 percent royalty rate. The suit was settled out of court, and the band re-signed with the label. By then, Metallica recognized the changes on the rock landscape epitomized by Nirvana, and in 1996 the band fully stepped away from its early lyrics of blood and guts and explored some nonmetal influences for an updated, almost alternative-leaning sound on Load (Number One). The album continued the band's string of hits with "Until It Sleeps" (Number 10), "Hero of the Day" (Number 60) and "King Nothing" (Number 90). Metallica also sought to change their image: Band members cut their hair, and the abstract album cover by controversial photographer Andres Serrano (famous for his work Piss Christ) depicted a mixture of blood and semen. Not all fans were pleased.

More confusion followed when Metallica headlined the alternative rock-themed Lollapalooza Tour in 1996. That year, the band also made a surprise stop at the Whisky-a-Go-Go in Hollywood for the 50th birthday party of Lemmy of Motörhead, appearing at the club all dressed like the metal veteran and performing a full set of Motörhead songs. In 1997 Metallica finished songs left over from the Load sessions for the heavier ReLoad (Number One), which included vocals by Marianne Faithfull on "The Memory Remains" (Number 28). The album also contained "The Unforgiven II" (Number 59). The next year, Metallica combined the original Garage Days Revisited EP with 11 new covers and various B sides for the two-disc set Garage Inc. (Number Two). A live collaboration with the San Francisco Symphony (arranged and conducted by Michael Kamen) was recorded for 1999's S&M.

In 2000 Metallica led a battle over the rights of recording artists against Napster, a popular music file-sharing Website where fans could download music (including Metallica's) for free. Metallica not only responded with copyright-infringement suits against Napster but demanded that the estimated 335,000 Napster users who had ever downloaded a Metallica track be permanently barred from the service. To critics it was a confounding strategy that inevitably targeted some of the band's most rabid followers. Despite a fan backlash, the controversy failed to derail that year's successful stadium tour with Korn and Kid Rock.

In 2001, Newsted left the band, citing his tension with Hetfield. That same year, directors Joe Berlinger and Bruce Sinofsky (Paradise Lost) began filming the band for a documentary, which would later be released in 2004 as Metallica: Some Kind Of Monster. The movie chronicled a turbulent two-year period in Metallica's history, during which Hetfield went to rehab, the group's management hired a motivational coach and the three remaining members struggled to record St. Anger (Number One, 2003). Produced with Bob Rock (who also played bass), Anger was a belligerent and sometimes tinny-sounding effort that put off some longtime fans. The title track was a moderate success, winning the band a Grammy.