Kucherov, who also won the Hart in 2019, edged Edmonton Oilers star Connor McDavid in voting for the award by the Professional Hockey Writers Association.
He finished 10 points ahead of three-time winner McDavid in the closest vote since 2002, with Nathan MacKinnon of the Colorado Avalanche coming in third.
Russia's Kucherov piled up 130 points this season, scoring 44 goals and delivering 86 assists in 76 games.
That included a 10-game stretch from December 20-January 12 when he had 10 goals and 15 assists.
The 32-year-old, who is a five-time finalist for the award, is the third player to go seven-plus years between Hart Trophy wins, joining Jean Beliveau (eight years) and Sidney Crosby (seven years).