In 2010, he took a shot at the ninth season of American Idol but lost his "golden ticket" place due to his legal status and residency considerations.

Semple and the four other contestant winners (Anton Gordon, Matthew Johnson, Daniel Pearce and Jamie Shaw) went on to form the group One True Voice.

A few weeks later it was announced that Daniel Pearce, who as arranger and co-writer of some of their songs had quit the group to pursue a solo career.

In 2006, Semple moved to the United States and joined Chicago-based rock band 7th Heaven as their lead singer.

In 2012, Semple left the band and was replaced by Anthony Fedorov, a contestant finalist on the fourth season of American Idol.

Semple said Simon Cowell was reportedly "unhappy" he did not tell his band members 7th Heaven in advance about his audition.

[4] Another former One True Voice band member Daniel Pearce had attempted a comeback less than a year earlier in 2009 on the sixth season[5] of the UK The X Factor.

With members Johnny Jannotti (formerly of Chasing the Day), Drew Johnson (formerly of Ordinary Outcasts), Amy Jay (formerly of Cat Fight) and Charley Bredrup (Fletcher Rockwell and The JR Miller Project).

Following interim guitarists Paulie Felice (of Lexington, KY) and Stevie Craig, the position was permanently filled by Valentine Bennett (of McHenry, IL).

In 2016, Semple founded the progressive rock band The Cyberiam with keyboardist, Frank Lucas, and Lateralus drummer Tommy Murray.

The Cyberiam have played at several progressive rock festivals, Progtoberfest IV in 2018, ProgStock in 2019, Marillion Couch Convention in 2020, and ProgPower USA in 2022 receiving a host of accolades.

In the debut episode of the season broadcast on 21 September 2015, he sang "I'll Be There For You" with two of the four judges, Adam Levine and Gwen Stefani turning their chairs.