The 26-year-old Republic of Ireland international striker has signed a three-and-a-half year deal and completed the relevant paperwork on Friday morning.
Long, who first came to prominence in this country as a frequent goalscorer during his time with Reading, has been courted by the Tigers since last summer’s transfer window and he is delighted to now be a part of Steve Bruce’s squad.
“I finally got the deal signed. I’ve met all of the lads today, and everybody seems really friendly. It’s a club that’s on the up, and I’m delighted to be a part of that,” said Long.
“I’m lucky that I’ve had a few inside informers letting me know what it’s like up here. They all love it up here, and they’re excited by what is happening at the club.
“After meeting the manager, and respecting what he’s done as a player and a manager, I was happy to start a new part of my career here and hopefully I can score a few goals to take us further up the league.”
Long has been allocated the number 21 shirt.