He turned professional in 2005 after a successful amateur career. He qualified for the second tier Challenge Tour by reaching the final stage of qualifying school. He narrowly missed out on graduating to the elite European Tour three times by ending the 2006, 2007 and 2008 seasons just outside the top 20 on the Challenge Tour Rankings.
He finally gained his European Tour card for 2010 by finishing in 17th place on the rankings in 2009.
McArthur has two wins on the Challenge Tour: the Reale Challenge de España in 2008 and the Doctorate+Doctorate Real Slovakia Challenge in 2014. 2002 Scottish Amateur Championship Challenge Tour wins (2) Other wins Amateur Street Andrews Trophy: 2004 (winners).