The 17-year old prop has signed a three year deal, and he’ll be on dual registration with Oulton Raiders Under 18s.
Brown is an Ireland international at both Under 16 and Under 19 level, and he was named player of the tournament in the Under 16s Four Nations, and picked up the player of the match award against Wales for the Under 19s international in the Autumn.
After starting playing rugby league at Stanningley, he’s spent the last two years at Normanton Knights.
He was brought to the Knights’ attention by Ireland coach and Knights assistant, Ged Corcoran.
Head coach, Mark Applegarth said: "I’m really impressed with Jack. He’s really responding well to the training environment.
"He’s got a really good head on his shoulders which is a credit to his upbringing and his mum and dad.
"Ever since our first meeting I was blown away with how mature he is. I think over the next few years he can be anything he wants to be.
"We first noticed him when Ged Corcoran mentioned him to us as a kid that’s got potential and he’s certainly got that."
On joining the Knights, Brown said: “It’s a dream come true. I’m over the moon. It’s nice to have the opportunity.”