The Irish playmaker missed a second-half penalty during the 1-1 draw with Preston at Carrow Road on Saturday when he attempted to nonchalantly chip the ball in.
But he made amends when he scored one and was fouled for another penalty as Norwich extended their unbeaten run to six games and ended Leicester's unbeaten home league run which stretched back to September.
Norwich took the lead in the 21st minute when Hoolahan headed in Andrew Surman's corner from six yards, his 10th goal of the season. But the lead lasted just two minutes as Richie Wellens levelled with his first goal since December, nodding in Bruno Berner's delivery.
The Canaries moved back in front four minutes into the second half from the penalty spot. Hoolahan was brought down by Matt Oakley and Holt, who took over penalty-taking duties, made no mistake for his 17th of the season.
They extended their advantage a minute before the hour when the recalled Aaron Wilbraham, on his 13th appearance, scored his first goal for the club with a neat finish. Substitute Paul Gallagher netted a consolation deep into injury time for the Foxes.
Leicester, without a win in three matches, had the first opening but Souleymane Bamba headed a Matt Oakley corner wide.
Norwich, who have failed to score in only four of their 35 Championship outings this season, responded but David Fox was also off target with a 25-yard free-kick.
Aiyegbeni Yakubu had gone three games without a goal for Leicester and headed over from 12 yards while strike-partner Darius Vassell then had the first shot on target which was comfortable for Norwich goalkeeper John Ruddy.
The game then sparked into life with two goals in three minutes.
First, Hoolahan made some amends when he nodded Norwich ahead but Leicester produced an immediate response through Wellens.
Andrew Crofts came close to restoring Norwich's lead when his header from another Surman centre just cleared the bar.
Play swung from end to end as first Yakubu had a weak shot easily saved by Ruddy before Andy King's effort trickled wide, the latter then heading wide from close range.
In between, Wilbraham could not keep his header from Marc Tierney's cross on target for the Canaries.
Yakubu had a further two attempts which both failed to trouble Ruddy while Surman first shot wide before being denied by Foxes keeper Ricardo in first-half injury time.
Norwich made an excellent start to the second half when Holt converted from the spot, his fifth goal in seven matches,
The captain then teed up Surman, who headed wide, before Vassell fired into the side-netting and Bamba shot straight at Ruddy.
Wilbraham then cut inside and finished past Ricardo at his near post to hand Norwich a two-goal cushion.
Leicester nearly pulled a goal back with 21 minutes left but Ben Mee headed wide with Ricardo then preventing Wilbraham from making it 4-1.
Gallagher did net a second for the Foxes but it was too late.