The earliest releases from Sem were around 2005, an instrumental mixtape series called 'Delivery Boy'. Then followed 'The Remixes' mixtape series which featured bootleg remixes mixing UK Grime and Electro with Pop acapellas. 'The Remixes Vol II' featured as compilation of the month in dance culture magazine Mixmag.
Sem's first production credit was for Highly Rated In The Hood's single 'Breakin The Scene' in 2006  which featured highly controversial Grime MC Crazy Titch on the chorus, Crazy Titch was arrested and sentenced to life in prison for murder during the promotion of the song. The video is rumoured to be the first ever banned and removed from Channel AKA out of respect for the victim's family. Sem later released an instrumental version of the track without any of the MC's originally featured on the final 'Delivery Boy series' release.
Semothy soon moved away from the Grime scene and gained industry attention from the likes of Zane Lowe in 2007 after several tracks he worked on with longterm friend Plan B featured on a bootleg Mixtape that the pair had worked on over the years called Paint It Blacker. In 2007 Sem also placed second in a Scratch Magazine's remix competition  judged by The Fixxers (DJ Quik and AMG) for their Interscope single "Can U Werk Wit Dat".
In 2010 Semothy signed a three-year publishing deal with Major Music/BMG Publishing and became part of the Biffco/Biff Stannard songwriting/production team. With Biffco Semothy worked on music for the X-Factor live show and many unreleased tracks for artists such as Leona Lewis and Aiden Grimshaw and eventually programming song parts for One Direction song 'I Want'  which featured on their triple platinum selling debut album Up All Night)' In December 2010 it was also announced that Propellerhead will be sponsoring Jones.
Several tracks from the 2014 Maggie Norris directed production 'The Realness' were written by Kath Gotts and produced by Semothy Jones. The show ran over two months later 2014 and received much praise from critics and the press "The production blazes up its grimy streets powered by pure passion.” The Times