Clemente joined Testament when they were still called Legacy. Clemente recorded the debut album The Legacy and served as Testament's drummer on The New Order, Practice What You Preach, Souls of Black and The Ritual. In 1992 he left the band at the same time as guitarist Alex Skolnick did. Clemente moved to a more stable career outside music, but agreed to share drum duties in 2005 during the classic reunion line-up in London. Unable to perform touring duties - after not having played a full set for 13 years - he didn't rejoin Testament. But Clemente has called the London show one of the top points of his life.
Clemente is known as the thrash beat drummer, because he almost exclusively plays thrash beats with his snare, bass and hi-hat.