The 23-year-old halfback, currently on loan at Castleford Tigers, has been enjoying a fine season. He has scored five tries and notched 64 goals, using a unique kicking style.
While Salford owner Dr Marwan Koukash recently stated he was keen to keep the player, Hull have agreed a transfer fee with the Red Devils.
He joins the Airlie Birds on what they describe as a “long-term contract”, and confirm that they also beat two rival Super League clubs to the player’s signature.
“I liked the opportunity at Hull FC because everything I have seen and heard really appealed to me,” said Sneyd.
“It looks like a good challenge for me and a club that wants to go places. It’s exciting to know I can be part of that.
“I hope I can build a career here. There seems to be a good mix of youth and experience at the club and hopefully I can help out there as well.
“Lee Radford seems to know what we he wants and where he wants to take the club which was very exciting to hear as a player.
“It’s a side where I feel I can achieve something as an individual and as a team. Things seem to be heading in a positive direction.