Musician P Diddy gave Montana, 31, the USD 1 million cheque as a bonus for being his Bad Boy Records artist.
On Christmas, Montana uploaded a photo of him with Diddy and several people holding the oversized copy of the check, reported Female First.
"Shout out to @iamdiddy for that million dollar gift bonus #happyholidays," Montana wrote.
The charity helps children in the New York neighborhood. Montana was born Karim Kharbouch in Morroco but he and his family migrated to the US and settled in South Bronx for years.
He also donated 100 pairs of Reebok shoes, computers and clothes to Bronx students under I Will Graduate program. The charity is dedicated to empower youth by promoting education and positive decision making.