The 24-year-old, who has made over 80 appearances for the Giants, has signed a 12-month deal and joins Lachlan Coote, Frankie Halton and Tom Garratt among the new faces at Craven Park from next season.
Hull KR coach Tony Smith said: “Sam is looking for a change and he’s got a bit to prove himself.
“He brings a whole lot of versatility to us as well as ambition. Sam wants to be successful and he’s chosen to come to us to be successful.
“I think Sam sees himself mostly at centre but he’s able to play wing, currently playing in the halves and second row.
“He brings a whole lot of versatility to us as well as ambition. (Sam) wants to be successful and he’s chosen to come to us to be successful.
“It’s a great criteria to have. Anybody who wants to be a part of us and has a strong desire to wear the badge – that’s got to be the number one.
“He sees what we’re doing here and wants to be part of it. To make himself better and help us become stronger.”
Earlier this week, Hull KR announce the signing of prop Garratt from Championship side Dewsbury on a two-year deal from 2022.
Smith said: “We’ve been really impressed with what form he’s in. He’s really stood up to a lot of rigours of the Championship and stood out.
“He’s a big strong, ambitious young man with some maturity. Probably in his prime for a prop.
“(Tom) feels he’s ready for the full-time environment and wants to throw everything into becoming a full-time player and fulfilling his ambitions.
“He’s the right mould of what we’re looking for, to give us more depth and more go forward.
“I can’t see any reason why he won’t be a success at Super League level, we’ve identified that in his ability but also in his ambition and his drive.
“I’m really excited about the addition and what Tom’s going to bring to us.”