Hardbottle, 25, came through the youth system at Leeds and joined York in 2010.
He has spent the past three seasons in Australia, and will link-up with the Hawks at the start of September ahead of their assault on the play-offs.
Hawks Director of Rugby Darren Williams said: “It’s certainly been a busy week at the club and Luke returning home is the icing on the cake, he has signed a deal until the end of the season and also agreed for 2015.
“He is a hard hitting back row forward with a no nonsense approach who wanted to play for his home town team. He had been approached by other clubs but was keen on a move close to home as he has a young family to support.”