Before joining Metallica, Hammett was a member of the band Exodus, an influential group in the Bay Area thrash metal scene. His transition to Metallica marked a significant turning point in his career and the band's trajectory, introducing a new level of musical complexity and depth.

Hammett has co-written some of Metallica's most iconic songs, including "Enter Sandman", "The Unforgiven", and "Fade to Black". His songwriting contributions often highlight his innovative guitar work, blending seamlessly with James Hetfield's rhythm guitar to create the band's signature sound.

Beyond his musicianship, Hammett is known for his collection of vintage horror and sci-fi movie memorabilia, which has been showcased in art exhibits. This passion for horror has also influenced some of Metallica's music videos and stage designs, adding another layer to the band's dynamic performances.

Hammett's early fascination with horror movies and his interest in expression through music led him to develop a signature style that combines melodic elements with aggressive metal techniques. His solos are known for their emotion, precision, and incorporation of the wah pedal, becoming a defining feature of many Metallica songs.