The Nigerian international, 24, scored five goals in three league appearances for the Foxes in the lead-up to the international break last month, including his first Premier League hat-trick against Sheffield United.
Iheanacho, who became a regular partner with Jamie Vardy in front following the absence of James Maddison and Harvey Barnes, also scored league goals in the 2-1 win at Brighton and the 1-1 draw against Burnley.
The young striker won the award ahead of Chelsea defender Andreas Christensen, Tottenham striker Harry Kane, West Ham’s Jesse Lingard, Manchester City’s Riyad Mahrez, Leeds goalkeeper Illan Meslier, Manchester United defender Luke Shaw and Brighton’s Leandro Trossard.
He was also named in Premier League team of the month alongside his teammate Wilfred Ndidi.
Leicester are third in the League table and Iheanacho will be looking to continue his goal-scoring form when they face his former club and leaders Manchester City
