It’s Iheanacho’s second goal in the Premier League this season after scoring a dramatic winner in a 2-1 win against Everton in his first league game of the campaign last Sunday.
Iheanacho got on the score sheet in the 41st minute to make it 2-0 after tucking home James Maddison’s perfect delivery.
Before finding the back of the net, Iheanacho set up Jamie Vardy for the first goal in the 20th minute.
He was later replaced by Harvey Barnes in the 64th minute.
Iheanacho’s Nigeria teammate, Wilfred Ndidi, was also impressive for Leicester City as he played the entire duration of the match.
Jack Grealish reduced the deficit for Aston Villa when he scored two minutes into first half added time to go into the break at 2-1.
Former Manchester United defender Johnny Evans restored Leicester’s two-goal advantage when he made it 3-1 On 49 minutes.
And with 15 minutes remaining in the game, Vardy put the game beyond doubt when he grabbed his second goal and Leicester’s fourth.
The win saw Leicester maintain a second spot in the table on 38 points, and are eight points behind leaders Liverpool.
The Foxes have now won eight straight league games and nine in all competitions so far this season.
At St James’ Park, struggling Southampton missed the chance to move out of the relegation zone as they lost 2-1 to Newcastle United.
Danny Ings put Southampton 1-0 up in the 52nd minute before goals from Jonjo Shelvey on 68 minutes and Federico Fernandez on 87 minutes, secured a 2-1 comeback win.
And at Carrow Road, another relegation threatened side Norwich lost 2-1 to Sheffield United.