Ryan played for Munster between 2009 and 2010 after being promoted from a development contract.
It was announced in Spring 2011 that Ryan was leaving Munster to join Lazio Roma in Italy. He moved to Zebre for the 2012–13 season.
In April 2014, it was announced that he would join Ulster on a 2-year deal from the 2014–15 season.
Ryan was included in the USA preliminary squad for the summer tests during 2012, being eligible through his American mother, but turned down the chance as to continue playing professionally in Italy.