Yorkshire born Mat Clark joined the Knights from county rivals Yorkshire Carnegie in June 2013 and quickly established himself as a starter in the Knights' midfield. Clark's try-scoring prowess was also quickly identified as the centre touched down for 20 tries in the Knights promotion winning 2013/14.
The 28-year old continued to be one of the Knights premier attacking threats upon the side’s return to the Championship and formed formidable centre pairings with the likes of Bevon Armitage and Will Hurrell.
Mat begins the 2017/18 campaign recovering from an ankle injury suffered against Ealing Trailfinders February 2017, but on his return started 14 times for the Knights.
As of late October 2018, the centre is closing on 100 appearances in a Doncaster shirt.