Metallica was formed in Downey, California in 1981 by drummer and son of a former tennis prodigy, Lars Ulrich, along with guitarist and vocalist James Hetfield who he met after each had separately placed classified advertisements in the AmericanThe Recycler. Ulrich, who had been influenced by the New Wave of British Heavy Metal, tried to start his own band before 1981 but was unsuccessful.

After building a loyal following through its role in the development of modern heavy metal, especially thrash metal (the most successful of the "big four" of thrash metal, which also included Megadeth, Slayer, and Anthrax) in the mid-1980s, the band broadened its audience in the early 1990s. Since then, the band has stood as the most commercially visible example of the metal genre.