American Scheffler won his maiden major at the Masters this year in addition to four other Tour victories, the most for any player during the 2021-22 season.
The award was voted for by fellow PGA Tour members, with Scheffler, who was also Rookie of the Year in 2020, getting 89% of the votes.
"On behalf of the PGA TOUR, congratulations to Scottie on his remarkable season and his unprecedented achievements," said Tour commissioner Jay Monahan.
"Undoubtedly, one of the highest compliments a player can receive is the endorsement from his peers, and the fact that Scottie's season was both dominant and consistent spoke volumes to the membership."
Northern Ireland's McIlroy also enjoyed a stellar season, winning his third FedEx Cup title while Australian Smith claimed his first major at The Open in July before defecting to the Saudi Arabia-backed LIV Golf Invitational Series last month.
