The Spurs' forward received 547 points and 84 first-place votes, beating out Draymond Green of the Warriors and Hassan Whiteside of the Heat.
San Antonio allowed the fewest points per game in the league this season, beating out the second-place Utah Jazz by three points. Leonard was a big part of that feat, as the Spurs' defensive rating was at 94.9 with the forward on the court, and 99.2 with him off.
The first-time All-Star this season recorded 1.8 steals and 1.0 blocks per game, ranking fifth in defensive plus-minus. That rank made him the only non-power forward in the top 25 in that category.
The Spurs' star becomes the first perimeter player to win the award since Sidney Moncrief did so with the Milwaukee Bucks in 1982-83. He is also the first non-big man to win it since Ron Artest with the Pacers in 2003-04. He can get it done on the offensive side of the ball as well, scoring 20 points in the Spurs' Game 1 win over the Grizzlies, as he hopes to lead them to another NBA Finals.