Former Terrier Gary Taylor-Fletcher lit up a low-key end-of-season match with a classy first-half strike and skipper Wes Morgan tapped in unmarked from a corner on 75 minutes as Nigel Pearson's side moved within a point of three figures.
Taylor-Fletcher was denied a second goal on 50 minutes when Adam Clayton cleared. Town midfielder Clayton sported a beard dyed blue and white, having raised £3,000 for charity by growing his whiskers since last year.
Leicester rattled the bar on 24 minutes, James with a blast from 30 yards after Huddersfield defender Paul Dixon made a mess of an attempted clearance.
The opener came in the 31st minute when Matty James made a break from deep and fed Lloyd Dyer, who found Taylor-Fletcher on the overlap. The winger, a popular player at Huddersfield from 2005 to 2007, curled in off the left-hand upright.
The home side should have levelled on 43 minutes when Sean Scannell raced to the byline past full-back Paul Konchesky. He cut the ball back for the unmarked Adam Hammill, who could only produce a tame shot from close range which was cleared off the line.
Huddersfield had chances either side of the break, although visiting keeper Kasper Schmeichel was rarely tested.
Having won the title at Bolton in midweek, Leicester rarely got out of second gear in the first half but did not need to find top form as Huddersfield made themselves safe from relegation with a win at Yeovil last week.
The visitors built up a head of steam in the second half and could have won by more in front a sell-out 3,850 away following.
Town keeper Alex Smithies saved from Dyer on 53 minutes and then brilliantly made a point-blank stop to deny Chris Wood three minutes later.
Taylor-Fletcher, who is out of contract in the summer, was given an ovation from the home fans when he was substituted on 63 minutes.
Smithies kept out a shot from Dean Hammond before Morgan sealed victory with a side-footed finish from a James set-piece.
Smithies then clattered substitute Daniel Drinkwater on the edge of the box as they pair jostled for a high ball late on, but no foul was given.
Morgan ensured a clean sheet for Leicester with an acrobatic clearance of a Scannell cross five minutes from time with Nahki Wells waiting to pounce.