Paterson, 24, will move to Craven Park ahead of next season, and previously worked with Rovers head coach Craig Sandercock at Newcastle Knights.
He said: “I’m really excited about my move to Hull KR. I’ve been following the club for a while since Sandy (Craig Sandercock) and a couple of my old team-mates, Con Mika and Shannon McDonnell, went there. I rate Sandy very highly, not just as a coach, but because he’s also a great bloke who I know will help me both as a footballer and a person.
“I’m lucky I’ve got a British passport and playing in the Super League was always something I wanted to do so when the chance came up to play for Hull Kingston Rovers, I couldn’t resist. The timing is right for me and my young family to make the move. We’re all keen to get over there and experience a different lifestyle and culture and for me to play some good footy.”
Paterson scored 21 tries in 77 appearances for the Knights after making his debut in 2007, and moved to the Cowboys in 2011.
Sandercock said: “Cory is a great acquisition for Rovers and is a young player who has already achieved a lot in the game at a young age,” he said. “He brings all the qualities on and off the field that we are looking for. Cory is coming to Rovers for the right reasons and I am really excited to be able to work with him again.”