Three days after a 2-1 victory over then-leaders Crystal Palace, Neil Warnock's men got the better of the third-placed Foxes to record a first midweek success since they beat Nottingham Forest 4-0 some 364 days ago.
That night was a significant one for United as it was their first game since the death of club icon Gary Speed and they tonight remembered their former title winner, marking the occasion in style with another success.
Luciano Becchio scored the only goal of the game with an early penalty, meaning the Whites have yet to lose since they were acquired by GFH Capital last week.
Leeds were ahead inside three minutes, with the trickery of Sam Byram earning a penalty which Becchio converted for his 12th goal of the season.
Even through Leeds' fallow start to the campaign, Byram was impressive, and the teenage full-back ran at Jeff Schlupp and was brought down, although it took referee Mick Russell a little time to award the spot-kick. Becchio duly sent former team-mate Kasper Schmeichel the wrong way.
Leicester found it hard to mount a response to the goal, with Leeds' central-defensive pairing of Tom Lees and Alan Tait looking robust, and their first effort came from full-back Richie De Laet who charged forward and hit a cross-shot at Paddy Kenny.
The experienced keeper was barely troubled by the effort, though, but the same could not be said for Schmeichel at the other end when he had to spring into life to produce a brilliant one-handed stop after Paul Green dug out an impudent chip from a Jerome Thomas cross.
Martyn Waghorn was the next to flash a shot across goal, with the England under-21 striker going closer than any of his team-mates when he swivelled on a loose ball and hit a volley which grazed Kenny's bar and went away before the stopper had even seen it.
Waghorn nearly caught Leeds cold at the start of the second half, breaking clear to bare down on Kenny's goal before he hesitated and was crowded out, before Wes Morgan's free header at least forced the former Sheffield United keeper to make a routine save.
Leicester had clearly upped the ante from their first-half showing and substitute Anthony Knockaert forced Kenny to go full stretch to keep out a 25-yarder.
For all their pressure, though, Leicester could not find a way to get past Lees or Tate and Leeds held out, despite a late punt from Schmeichel rearing up and bouncing off the top of Kenny's bar.