The 22-year-old has made 14 European appearances in 2 seasons at the Falcons and will battle it out for the number nine jersey with England half-back Ben Youngs.
"It was the ambition that the club (Leicester) has got and the things that I have seen people do down there in terms of winning titles," Young told The Journal.
"I want to be part of something like that, and to try and further my own chances.
"There is real competition at the club with Ben Youngs being in the England squad, James Grindall who I know from Newcastle and a younger prospect like Sam Harrison, and I think that will be great in pushing me on as a player.
"It was a really tough decision - probably the most difficult of my life.
"I am from the area and it has always meant a lot to me to represent the north east side.
"But I want to take on a new challenge and see what I can do with my life.