Aaron Gillespie delivered drums and vocals in Florida's Underoath, a band that evolved from a run of the mill Christian metalcore band into a fluid, dynamic and energized ock group that adeptly blends emotive melody, charged punk rock rhythm, and chunky, engaging bottom end. He had joined the group in 1997, and left in 2010.
Aaron Gillespie also has a solo side project called The Almost, featuring Kenny Bozich on drums.