The on-loan from Sheffield United midfielder's superbly struck 41st minute winner will have done much to help turn his dream of a permanent move to the Walkers Stadium into reality.
There were anxious moments right up until to the end for Leicester after a brilliant performance by Joe Murphy had kept their lead to a minimum.
Murphy's first stunning save came on 20 minutes when Steve Howard's header from Joe Mattock's superb cross looked goalbound until the agile keeper intervened with a stunning finger-tip save.
Then on the half-hour mark, Murphy foiled City again when he blocked Matt Fryatt's header after another pinpoint cross from Mattock.
Leicester broke through on 41 minutes when Howard nudged Richard Stearman's cross into the path of Hendrie, who expertly arced an angled shot into Murphy's top far corner from 14 yards.
Fryatt almost doubled City's lead on 69 minutes when his cushioned shot from a Howard knock down drifted just wide.
Scunthorpe had what looked like a legitimate penalty claim turned down on 75 minutes when a Paul Hayes shot struck Stearman's arm.
But City escaped to race downfield where Howard fired just over after good work down the right by Leicester debutante David Bell.
Murphy defied City again on 82 minutes when he twisted in midair to tip over another Fryatt header before Hendrie shot narrowly wide.
And just before the end, Murphy produced another wonderful save when he reacted quickly to push away Fryatt's goalbound drive.