Diarmaid joined Leinster at the start of the 2013/14 season having worked with the squad as an intern for 2012/13. He was initially appointed to the post of Academy Rehabilitation Coach, a role he held for the 2013/14 season, before being promoted to Rehabilitation Coach with the Senior squad for 2014/15 season.
He was educated in Institute of Technology, Carlow where he obtained a National Certificate in Physiology & Health Science as well as an Honours Degree in Sports Rehabilitation.
After graduation he established his own private practice in Ballyfermot and began working with St. Patricks Athletic FC in the League of Ireland Premier Division. During this time Diarmaid completed his Masters in Football Rehabilitation from Edgehill University, graduating in 2011.