Featuring in many television series and commercials whilst still a child at school, aged 10 he ventured into Musical Theatre where he played the lead role Gavroche in London's West End musical Les Misérables at the Palace Theatre, before becoming the first person to play the role of the Artful Dodger in Cameron Mackintosh's production of Oliver!

In 2006, he then signed with Universal Records becoming one of five members in the new boyband Lexington Bridge, a mixed American-British act, that went on to achieve five number 1 hits across seven countries in Europe.

During this time Dax also performed as a dancer for Little Mix (2012), X Factor Live shows (2009 – 2010), Alexandra Burke (2009) and for seven of JLS's UK Tours (2009 – 2014).

The premises would become the UK's most popular dance studios for public classes and a home for the entertainment industry supplying rehearsal space for the elite projects.

In 2008, O'Callaghan became choreographer for Germany's reality TV Show Popstars, working with the winning group named Room 2012.

In 2011 he released his first UK single called "Broken", fronted by ex-EastEnders actor Mohammed George, which featured Dax O'Callaghan as well as being written by him.

The song was used as an anthem for the Ben Kinsella Trust and all royalties from sales were donated to the charity helping the fight against knife crime within the UK.