The 49-year-old led the Foxes to four league wins out of four during the first month of the year, including a 6-1 home win over Huddersfield and a 4-0 victory at Bristol City.
They also triumphed over Middlesbrough and Wolves to lift themselves up to second in the table behind leaders Cardiff.
Pearson beat off competition from Burnley's Sean Dyche and Brighton & Hove Albion boss Gus Poyet to the award, which he won for the first time with the Foxes back in February 2010.
Walsall's Dean Smith is the League One manager of the month after four wins in five games lifted the club from 16th to 11th in the table.
Gillingham boss Martin Allen claimed the League Two award as three wins and a draw from their five games kept up the club's push for promotion.
Former Charlton and West Ham boss Alan Curbishley, who is a member of the voting panel for the awards, was full of praise for Championship winner Pearson.
"It's been a fantastic month for Nigel Pearson with Leicester City winning all of their games while also scoring freely in the npower Championship," said Curbishley. "The Foxes are now in a great position as we approach the business end of the season."