Myler signed for Salford from Widnes on a three-year deal in 2008 and contributed to Salford winning the National League One title, scoring 25 tries in 32 appearances, and winning numerous awards as well as the Co-Operative Player of the Year award. On 14 February 2009 Myler made his Super League début against Crusaders, scoring a try in a Salford victory.
In 2009, he signed a four-year contract with Warrington worth around £200,000, making him the most expensive teenage signing in Rugby League history. Myler was offered a new contract which allegedly would have made him the highest paid player in the history of Widnes. According to agent Martin Offiah he rejected the deal, instead favouring a four-year deal with Warrington.
In 2015, he declared he was interested in playing the NRL the next year as he wanted a new challenge. Manly were rumoured to want Myler after the departure of halves pairing Kieran Foran and Daly Cherry-Evans. However, on 10 July 2015, it was confirmed that Myler would stay in the Super League, signing a two-year deal with Catalans Dragons from 2016.
On 27th June 2017 it was confirmed Myler had signed a three year deal to join Leeds Rhinos starting from the following season
Myler has represented both the Lancashire and England U17s at Academy Level.
He was named in the England training squad for the 2008 Rugby League World Cup. He was named in the England team to face Wales at the Keepmoat Stadium, Doncaster prior to England's departure for the 2008 Rugby League World Cup. He made his England début in the victory over Wales on 10 October 2008.
Myler represented England against France on 13 June 2009. He started the game at scrum half and scored 30 points in the 66-12 England victory.
Myler was not called up to the England RL side for the Four Nations in 2011, however he was selected in the England Knights where he put in two man of the match performances but was still not called up.
In March 2012 Myler became engaged to then Blue Peter presenter Helen Skelton. They married in December 2013, and Skelton gave birth to their first child, a boy named Ernie, on 19 June 2015. On 27 November 2016, Skelton revealed she is expecting their second child, due in Spring 2017. their second son, Louis was born in April 2017.