Josh Allen and Devin Bush were the other finalists for the award, but Bosa was the clear top choice after an outstanding first season in the league.
The 2019 No. 2 overall draft pick lived up to his lofty expectations with 47 tackles, nine sacks and a team-high 16 tackles for loss as an anchor for the No. 2 defense in the NFL in yards allowed.
He also added two fumble recoveries and an interception nearly returned for a touchdown as he continually made impact plays.
While the standard numbers were impressive, Bosa truly separated himself with his consistency even without getting to the quarterback.
Per Pro Football Reference, the 22-year-old finished tied for fifth in the NFL with 24 hurries, trailing only elite established pass-rushers like Aaron Donald, Khalil Mack and Cameron Jordan, as well as his brother, Joey Bosa.
According to Pro Football Focus, Bosa set a rookie record with 80 overall pressures, 14 more than anyone since it tracked stats in 2006.
This type of production helped the defensive end earn a Pro Bowl selection in his first season as well as some votes for the All-Pro team. He's also a major reason the 49ers are set to play for the Super Bowl on Sunday against the Kansas City Chiefs with three sacks in his first two playoff games.
It eventually landed him the league's Defensive Rookie of the Year award as he begins what could be an outstanding career with San Francisco.