Murrell, 27, was part of the Rovers team that earned promotion to Super League in 2006, but was not offered a new contract at the end of this season.
Coach Karl Harrison said: “Scott has been our main target for a few weeks now and, after lengthy negotiations, we have managed to get his signature after beating off stiff opposition from some Super League clubs.”
Murrell came through the academy at Leeds, and is capable of playing at stand-off, hooker and loose forward.
He added: “I am really pleased to be joining Karl at Halifax. He has put together a really strong pack and some good backs and I look forward to working with them and getting to know the lads.”