The fine is the maximum allowable amount under the collective bargaining agreement, and stems specifically from punching Rangers forward Pavel Buchnevich. Player safety did not view the ensuing slam on superstar Artemi Panarin as suspendable, per ESPN's Emily Kaplan.
Wilson was given four minutes for roughing and a 10-minute misconduct.
Panarin left the game with a lower-body injury and is reportedly likely to miss the remainder of the Rangers' season. He and Buchnevich both received roughing minors on the play.
The Rangers were predictably incensed by Wilson's actions after the game.
Wilson has been suspended five times in his career, most recently in March when he received a seven-game ban for boarding Boston Bruins defenseman Brandon Carlo.
The Capitals and Rangers face off again Wednesday.