With an electric mixer fitted with the whisk attachment, whisk heavy cream to medium-stiff peaks. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat cream cheese and sour cream until smooth, about 2-3 minutes, stopping to scrape down sides as necessary.
Beat in sugar and cinnamon, scraping down sides as necessary.
Add pumpkin purée, 1 cup at a time, beating until smooth after each addition.
Stir in vanilla.
Scrape sides and bottom of bowl to make sure everything is mixed completely.
Fold in the whipped cream.
Pour into the prepared graham cracker crust.
Cover the cheesecake with plastic wrap and refrigerate overnight.