WARATAHS hold onto Foley's understudy
The 22-year-old has been in NSW for two seasons and have accumulated just two caps.
Despite his shortage of Super Rugby game time, the former Junior Wallaby flyhalf was included in the senior international training squad ahead of last year's Melbourne June Test.
Mason, born in Queensland, said the decision to recommit to the NSW Waratahs was easy.
"This is my home now and one of the main reasons for wanting to continue to play my rugby in New South Wales is because I have learnt a lot and progressed as a player since moving here.
"I have found my feet in rugby union this year and NSW is the place for me to continue my development," Mason said.
Waratahs Assistant Coach (Backs), Chris Malone, rates Mason as one of the game’s most gifted young players.
"Mack has an incredibly mature head on his shoulders, which is a huge reason why he is so important to the future of the NSW Waratahs. He brings an assured presence to the game and continues to develop his core skills set around five-eighth.
"Mack is very driven and he is constantly striving to be the best, and that is one of the main reasons he will succeed here," Malone said.