Matt Fryatt's second-half header was enough to clinch the points for Leicester as they finally broke down a resilient Plymouth side.
Leicester were frustrated by Plymouth as they failed to make their superiority count in a first half most notable for a lack of goalscoring opportunities.
Rob Kelly's side had taken just one point from their previous two Coca-Cola Championship matches against Preston and Coventry, as had Plymouth, who drew at Millwall and then lost at home to Luton.
Both sides started slowly with chances at a premium in the opening 10 minutes, but it was the home side who had the first effort on goal with Joey Gudjonsson's speculative shot from distance flying well wide of the target.
Leicester's Richard Stearman was the first player to be booked after just 11 minutes for a foul on Tony Capaldi and Plymouth's Lilian Nalis then tried his luck from 25 yards but failed to get his shot on target.
Gudjonsson carved out another opportunity for Leicester after 19 minutes but his well-struck shot from 18 yards failed to trouble Plymouth goalkeeper Romain Larrieu.
But it was his opposite number Paul Henderson who prevented the visitors opening their account two minutes later.
Plymouth were awarded a free-kick after David Norris was fouled by Andrew Welsh and Henderson reacted superbly to keep out Capaldi's 25-yard effort.
Despite that scare the home side dominated the first half territorially, but were unable to make anything of several promising attacking moves.
Henderson was tested again shortly after the re-start but was equal to David Norris' shot from 20 yards.
But Leicester responded swiftly and carved out a chance of their own as Gareth Williams' outswinging corner from the left found Stearman who sent a header just wide and shortly afterwards a long-range strike from Stephen Hughes missed the target.
Plymouth then made a tactical switch after 54 minutes, bringing on Nick Chadwick for Leon Clarke.
But it failed to have the desired effect as the home side took the lead just 60 seconds later.
A cross from Welsh found Fryatt who headed home from close range to put his side in the driving seat.
Plymouth made another switch on the hour with Akos Buzsaky coming on in place of Lee Hodges and just three minutes later they brought on Anthony Pulis for Paul Connolly.
Buzsaky tried his luck from 20 yards after 65 minutes but failed to get his shot on target.
Chadwick sent another shot wide 15 minutes later before testing Henderson with a superb effort from 30 yards three minutes from time which the goalkeepe tipped around the post, but it was Leicester who held out despite Plymouth's late rally.
Teams:
Leicester Henderson, Stearman, Johansson, McCarthy, Maybury,Hughes, Gudjonsson, Williams, Welsh (Tiatto 78), Hume,Fryatt (O'Grady 82).
Subs Not Used: Douglas, Sylla, Gerrbrand.
Booked: Stearman.
Goals: Fryatt 55.
Plymouth Larrieu, Connolly (Pulis 63), Doumbe, Aljofree,Hodges (Buzsaky 62), Norris, Wotton, Nalis, Capaldi,Clarke (Chadwick 54), Pericard.
Subs Not Used: McCormick, Reid.
Att: 22,796
Ref: P Joslin (Nottinghamshire).