The 22-year-old, who has made more than 60 appearances in the Betfred Championship, has joined Featherstone on a one-year contract.
Son of former Great Britain and Rovers prop Karl Harrison, he said: “I’m looking forward to the challenge of stepping up to a big club like Featherstone, who play in front of big crowds.
“I’m really just looking forward to getting stuck into pre-season now.
“Whenever Featherstone come to Batley their fans make it feel like a home game for them, so I’m really looking forward to playing in front of them every week.”
He added: “I’ve had three good years at Batley, particularly taking on Super League sides in The Qualifiers.
“I learned a lot, especially under John Kear in that first year, but I feel like I’m ready to move on and test myself at a bigger club now.
“One of the main reasons I wanted to come to Featherstone was to play outside the half-backs they’ve got.
“Obviously Martyn Ridyard’s really experienced and with Ase and Watson Boas joining from Papua New Guinea, I think we’re in for some really exciting times.
Of his family connection to Rovers, Harrison said: “Coming from a rugby league family means I’ve played it all my life, but I’ve always wanted to make a career off my own back, rather than through my dad’s name.
“His career went up another level at Featherstone though, so I think this is an area where I could follow in his footsteps.”
The Bradford Bulls Academy product has scored 17 tries for Batley and has also proved his versatility when covering at prop.
Rovers head coach John Duffy said: “James is a player who we have been looking at all year.
“He’s very capable in the back-row or down the middle and we know he can do big minutes for us.
“He comes from good stock and just wants to progress in his career.
“I’m looking forward to a big preseason from him and him adding value to us.
“He’s got a big future ahead of him. Quite a few clubs were after him and we’re lucky to have got his signature.
”There was competition from a club in the Qualifiers, but we’ve been looking at him for a long time and are very pleased to have him coming to Featherstone.”