Smile Empty Soul is a 3-piece alternative hard rock band formed while its members attended different Santa Clarita high schools: Sean Danielsen (guitar and vocals), Ryan Martin (bass), and Derek Gledhill (drums). For Anxiety, Derek Gledhill was replaced by Dominic Weir. Dominic was then replaced by Ryan's friend Jake Kilmer. Later on, Mike Booth joined as second guitarist but split by mutual agreement during their 2007 tour. As of 2018, the band's lineup consists of Danielsen, bassist Mark Young and drummer Victor Ribas.