Backhouse joined the Knights from Castleford Tigers in 2013.
Hunslet director of rugby Darren Williams said: “Ryan is a tremendous addition to our squad for 2015, at 21 his best years are in front of him and he comes with some glowing endorsements from people I respect in the game.
“He is a very powerful runner and impressed when he played against us this season for the Knights.
“This is a great opportunity for Ryan like alot of our new recruits for 2015 in their early twenties to really kick on next year.”
The player himself is looking forward to the chance to test himself at a higher level next season.
“I’m very grateful to Hunslet for giving me this opportunity to play in the Championship next year,” he said.
“I hope to put in some big performances and continue my development and kick on and do well with the Hawks.”