After guitarist Tim Agnello left Exodus in 1981, Gary Holt joined the band and has been the main songwriter and the most senior member of the group ever since. Following Kirk Hammett’s 1983 departure from Exodus to join Metallica, Holt kept the band going and during a lot of years, he and Rick Hunolt were referred to as the Exodus’ « H-Team » guitar players. Holt is the only member of Exodus who has played on every album.

Gary endorses guitars by ESP (signature models: ESP Gary Holt Liquid Metal Lava, LTD GH-600 Black, LTD GH-200 Black), previously was endorsed Schecter Guitar Research and has a signature model through them, but previously used Ibanez, B.C. Rich and Jackson Guitars. In October 2008, Holt released an instructional guitar video called « A Lesson In Guitar Violence ». He also produced Warbringer’s second album, Waking into Nightmares.

On February 12, 2011, it was announced that Holt would be temporarily filling in for Jeff Hanneman in the band Slayer. Holt would immediately join Tom Araya, Kerry King and Dave Lombardo for Slayer’s five-date Australian Soundwave Festival tour that began February 26.

In the fall of 2020, Gary Holt (guitars), Dave Lombardo (drums) and Derrick Green (vocals) have joined forces in Beloved Ghouls project to record a Halloween song called « Terrorized » produced by Ross Robinson with guest appearace by Jeremy Bolm and also with Jason Schimmel (keyboards) and Jeff Johnson (bass).