At 20 years old, the Alabama native is also the youngest rookie award winner since Jordan Spieth in 2013.
"Nick carved out his place in the PGA Tour record book," commissioner Jay Monahan said on Thursday.
"To begin 2024 as a collegiate golfer and end it with two PGA Tour victories and among the top-50 players in the FedExCup is truly impressive."
The award is voted on by PGA Tour members who played in at least 15 events during the 2024 season. Dunlap received 57 percent to finish ahead of fellow nominees Max Greyserman, Jake Knapp and Matthieu Pavon.
As a sophomore at the University of Alabama, Dunlap won The American Express in January to become the first amateur winner on tour since Phil Mickelson in 1991. He turned professional four days after the victory.
Dunlap then added to his historic season with a victory at the Barracuda Championship in July.
He finished 49th in the FedExCup standings, qualifying him for the Tour's 'Signature Events' in 2025 by virtue of finishing among the top 50.
Dunlap ended his amateur career as the No.1 in the World Amateur Golf Rankings. He won the 2021 US Junior Amateur and the 2023 US Amateur, joining Tiger Woods as the only players to win each title.
