David Ellefson is best known as the bassist and co-founder of the American thrash metal band Megadeth. He has also played in other bands such as Temple of Brutality, F5, Killing Machine and Hail!. He is considered one of the major contributors in the development of thrash metal, thanks to his aggressive and melodic playing style.

Since Megadeth disbanded in 2002, Ellefson has worked on various side projects and his own record label, EMP Label Group. Additionally, he has lectured and written books on bass techniques and music production. In 2004, Ellefson reunited with Megadeth and he has remained a member of the band to date. He was inducted into the Rock and Roll Hall of Fame in 2020 alongside the other members of Megadeth.