The 24-year-old front rower came through the ranks at Hull FC before moving to York in 2012.
“Were thrilled to announce Austin as our first new signing for 2016,” said Hawks director of rugby Darren Williams.
“Austin is a very direct runner of the ball and has progressed rapidly over the previous 2 seasons and we’ve kept an eye on his improvement since he came under our radar.”
Williams also hinted that more new recruits could be expected at the club shortly.
“We’re pretty close to agreeing new deals with several of or 2015 squad although inevitably some will move on to pastures new,” he said.