Lewis studied civil engineering for a year before turning to music. His mother was a shop assistant, and his father worked in management for a chemical company. Lewis attended Hawthorn High School His favourite subjects were science and history. His first concert, as a concertgoer, came when he saw Tesla at St David's Hall.
In September 2006, Lewis married his girlfriend, Amber Payne. They now reside in Malibu, California. On 24 February 2009, he confirmed on his Facebook page that he and his wife were expecting their first child.
Lewis is an avid Star Trek fan and owns a Star Trek uniform. He is a lifelong Everton fan. He surfs Santa Monica beach almost every day when he is at home. It was previously reported that Lewis was once a vegan who turned vegetarian, but in an interview with The Rock Radio Station in New Zealand, it was revealed that was not the case. He stated to the hosts that he enjoys his steak cooked "medium rare".