Leicester now sit in eighth place in the top-flight standings, while Huddersfield are now bottom as their wait for a league win this season is extended for another week.
Huddersfield have so far failed to hit the heights of their strong end to last season, but the visitors needed just five minutes to go ahead, with Jorgensen being well-placed to convert from close range after a flick on from Laurent Depoitre.
The goal heaped the pressure on Leicester boss Claude Puel - who had not guided his side to a win in the top flight since August 25 - but the home side were soon level when Iheanacho was on hand to provide the finishing touch after a counter-attack.
The East Midlands outfit dominated possession either side of half time without being able to apply a clinical touch in the final third, but a second goal finally arrived midway through the second period.
A free kick was awarded on the edge of the area, and Maddison stepped up to curl the set piece into the net for his third goal since joining from Norwich City.
Puel's team made sure of the points with 15 minutes remaining when Vardy got clear of the Huddersfield defence before lifting the ball over Huddersfield stopper Jonas Lossl.
LEICESTER CITY (4-3-3) Schmeichel; Amartey, Evans, Maguire, Chilwell; Ndidi, Mendy, Maddison (Okazaki 85'); Ghezzal (Gray 46'), Iheanacho (Albrighton 77'), Vardy
HUDDERSFIELD TOWN (5-4-1) Lossl; Durm, Jorgensen, Schindler, Kongolo (Pritchard 72'), Lowe; Kachunga (Diakhaby 57'), Mooy, Billing, Van La Parra; Depoitre