Goals from Iain Hume, Steven Howard, Dudley Campbell and Stephen Clemence swept aside Norwich, who fell apart once Darel Russell was show a straight red card for an horrendous two-footed tackle on Richard Stearman.
Leicester's first clear chance came on nine minutes when David Marshall was forced to twist in mid-air to tip over Clemence's hard volley.
After Ben Alnwick had comfortably saved a Ched Evans shot, there was controversy at the other end when Hume drove a free-kick into a defensive wall with loud claims from the Leicester players that the ball had hit a Norwich hand.
Marshall then saved spectacularly from Howard's header, before Leicester took a 22nd minute lead when Campbell slipped a pass to Hume, who drifted to his left before guiding the ball beneath Marshall.
Campbell was the provider again on 35 minutes, this time setting up Clemence whose 14 yard shot bobbled just wide.
Jason Shackell came to his side's rescue soon after the re-start when his last-ditch tackle prevented Campbell from connecting with Hume's cross.
But there was nothing Shackell could do to stop Leicester racing into a two-goal lead on 57 minutes when Hume's long ball caught the Norwich rearguard napping to give Howard the space to advance and thump the ball beyond the exposed Marshall.
The Canaries' frustration at falling further behind boiled over on 59 minutes when Russell was dismissed.
Depleted Norwich thereafter struggled to contain vibrant Leicester, who made the game safe on 77 minutes when Matty Oakley picked out Campbell who steered and angled shot beyond Marshall.
A fourth goal arrived on 82 minutes when Zsolt Laczko pulled the ball back for Clemence to drive home from eight yards.