Brown, 23, is Sheffield’s top scorer this season with 235 points in 28 appearances, and he will be joined in the Knights squad for 2013 by fellow half-back Jonny Presley.
He said: “I have enjoyed the past three seasons at Sheffield but I am really looking forward to a new challenge at the Knights. With the caliber of players that the club is singing I am sure that we will be in for a good season and I can’t wait to get started.”
Presley, 28, returns to the Knights having spent the 2012 season playing for Freemantle Roosters in Australia.
He said: “I am delighted to be re-joining the Knights. After a difficult two seasons, in which the club have been establishing themselves in the Championship, I believe that the club is now in a position to start climbing the ladder and I am aiming to work hard in pre season to ensure that I am part of that improvement.”
Head Coach Gary Thornton said: “When I was offered the job at York, my main priority was to sign a couple of quality, proven, and experienced half backs to replace Chris Thorman.
“In Simon Brown we have one of the most consistent and reliable half backs in the Championship. He has all the attributes I’m looking for. He can organise a team around the pitch and play to a structure, and in my opinion has the best kicking game in the Championship. His recent form for Sheffield in the play-offs has been outstanding and it is those kind of performances which made him my number one target. He was ready for a change having had three good seasons at Sheffield and I am delighted he has decided to join us for 2013.
“We are continuing to build our squad up, and I am delighted to bring Jonny Presley back to the club for next season. He’s spent some time in Australia where he has been getting some rave reviews and frequently putting in man of the match performances. He will give us a real attacking threat with his pace and footwork, and will be a good option for us at either half back or hooker.”