Moon's signing, for an undisclosed fee, was announced on 21 November 2012. He was expected to fill the void left by former Leeds centre Keith Senior, who retired through injury. Moon made his début for Leeds on 1 February 2013, he scored in the 2nd half and was awarded with the man of the match. Having made an excellent start to his Leeds career, forming an excellent partnership with winger Ryan Hall, which led him to sign a new contract with the club in May 2014, keeping him at Headingley until 2018.