Goals from Caleb Folan and Fraizer Campbell got Hull back to winning ways as they grafted to their first win in five league games.
Folan put Hull in front on 17 minutes, drilling home clinically after getting on the end of a Dean Windass pass.
Windass saw his second-half penalty - awarded after Bruno N'Gotty fouled the veteran striker - saved by Marton Fulop but Campbell reacted quickest to score.
Alan Sheehan and Carl Cort went closest for a Foxes side lacking in creativity.
Hull assistant boss Brian Horton:
"The response today was tremendous and Leicester hardly had a shot on target.
"We needed the three points and the players knew it throughout the week's training.
"Caleb showed what he is all about today and they couldn't handle him at all. We tried to go back to basics today and there were some good performances by the players.
"He's 6ft 3in and has an awesome build. He showed why the manager spent all that money on him earlier in the season."
Leicester manager Ian Holloway:
"We were well and truly beaten, they had more fight and determination.
"I don't agree with transfer windows but I've never needed one to open so quickly in my life. I've got a lot more work to do than I first thought.
"You have to have some sort of morale and spirit of togetherness in any organisation and we were devoid of all that today. It was totally unacceptable.
"I'm not going to be sacked in the morning, I'm going to be judged on the players I bring in and how quickly I turn this around. It was a bad, bad day."
Hull: Myhill, Ricketts, Turner, Brown, Dawson, Garcia, Ashbee, Marney, Hughes, Windass (Livermore 79), Folan (Campbell 72).
Subs Not Used: Duke, Doyle, McPhee.
Goals: Folan 17, Campbell 78.
Leicester: Fulop, N'Gotty, Kisnorbo, McAuley, Mattock, Kaebi (Cort 46), Clemence, King, Sheehan (John 46), Hume (Stearman 66), Fryatt.
Subs Not Used: Hayes, Kenton.
Booked: Sheehan, Mattock.
Ref: Graham Salisbury (Lancashire).