Bosa beat out Arizona Cardinals quarterback Kyler Murray, Oakland Raiders running back Josh Jacobs, Tennessee Titans wide receiver A.J. Brown and Philadelphia Eagles running back Miles Sanders via fan vote to earn the honor.
The No. 2 overall pick in the 2019 NFL draft played a significant role in the Niners' improvement from 4-12 in 2018 to 13-3 this season. The NFC champion 49ers will face the Kansas City Chiefs in Super Bowl LIV on Sunday.
Bosa was a force during the regular season. He registered 47 tackles, 25 quarterback hits, 16 tackles for loss, nine sacks, two fumble recoveries, one forced fumble and one interception.
Boasting a front four littered with first-round picks, the Niners ranked second in total defense, allowing just 281.8 total yards per game.
As good as Bosa was over the season's first 16 games, he has arguably been even better in two playoff contests with eight tackles, four quarterback hits, three tackles for loss and three sacks in wins over the Minnesota Vikings and Green Bay Packers.
If the 49ers are going to slow down 2018 NFL MVP Patrick Mahomes and the Chiefs' high-octane offense, they will likely need Bosa to make him uncomfortable in the pocket with regularity.
The Pepsi NFL Rookie of the Year award has been given out since 2002, and many of the NFL's best players have won it, including Ben Roethlisberger, Adrian Peterson, Cam Newton, Russell Wilson, Dak Prescott, Alvin Kamara and Saquon Barkley.
Bosa is just the second defensive player to earn the award, joining then-Detroit Lions defensive tackle Ndamukong Suh, who won it in 2010.