Tobias Hysen came off the bench to earn Sunderland a point in boss Roy Keane's first home game in charge.
He struck in the 65th minute, seconds after coming on, sending a skidding shot off Leicester's Darren Kenton and past keeper Paul Henderson.
Matty Fryatt gave Leicester a shock lead after 48 minutes, with a composed finish after Liam Miller's mistake.
Hysen almost added a second in the 69th minute, but he directed the excellent Ross Wallace's cross wide.
Sunderland boss Roy Keane:
"There were a lot of positives, but it is a good reality check for everybody at the football club, especially the players.
"It was a tired performance and I take responsibility. I was tempted to freshen things up, and I should have.
"But after going a goal down, the players responded well and showed the character I have spoken about."
Leicester boss Rob Kelly:
"I am pleased with the performance, but we are actually a bit disappointed that we are going back with just a point.
"We have got a very young team, an emerging team and for us to come and play in front of over 35,000 supporters in a high profile game, this is why you come into football, isn't it?
"It was terrific for all our players, not just our young players."
Sunderland: Alnwick, Neill Collins (Leadbitter 55), Cunningham, Varga, Robbie Elliott, Liam Miller (Hysen 65), Whitehead, Kavanagh, Wallace, Brown, Murphy (Yorke 15).
Subs Not Used: Ward, Danny Collins.
Goals: Hysen 66.
Leicester: Henderson, Kenton, Kisnorbo, McCarthy, Johansson, Wesolowski, Johnson, Hughes, Porter, Fryatt, O'Grady.
Subs Not Used: Logan, Maybury, Hume, Tiatto, McAuley.
Goals: Fryatt 48.
Ref: M Pike (Cumbria).