Stockwell joins the Knights from St George Illawarra, following a release. The young forward made his NRL debut in 2012 and has played 35 NRL games.
“Jack is big and athletic, he has a good motor on him and will bolster our forward pack,” coach Rick Stone said.
“At only 22-years of age, he obviously has a lot of footy in front of him.
“He was strong in the Under 20s but it has taken some time for him to find his feet in the NRL. He had a few injuries this year which minimised his game time.
“As a young player, with a lot of potential, we are really happy to secure his services and look forward to having him here at the Knights.”
The Club is also pleased to retain Houston on a two-year contract and Fa’alogo, who has signed a one-year contract.
Houston has played 154 NRL games while Fa’alogo, who is currently captaining Toa Samoa in the Four Nations tournament, has played 182 NRL games.
“There is a lot of NRL experience between Chris and Dave and we know they will be valuable to our young group of forwards coming through,” Stone added.