"I still feel I have a lot of learning to do but I know that St Helens is the best environment to do that in,"
"We have a great coaching team and players here and they will help me develop further. I'm really looking forward to kicking on in 2019."
Ex Saints legend Peter Sculthorpe MBE said "he was the best player on the pitch" in PNG.
“Matty is a great young player who showed that he is more than capable of performing at the highest level in Super League last season,” Saints Head Coach Justin Holbrook added. “He is an exciting talent who is professional and keen to improve and develop.
“I’m really excited about seeing him do that this season and beyond.”
The deal keeps the player at the Totally Wicked Stadium until the end of the 2021 season.