Five of the Capitals' goals came in the second period, during which they drove goaltender Ray Emery from the game.
Washington snapped a two-game skid in a meeting of the bottom two teams in the Metropolitan Division.
Nicklas Backstrom added two goals and Braden Holtby made 30 saves to record the shutout. Holtby evened his record at 5-5 with what was the eighth shutout of his four-year career.
Ward began the big second period by scoring 1:24 into the stanza. He added one with 3:35 to go in the period and then scored the only goal of the third on the power play.
Emery gave up four goals on 21 shots before being replaced by Steve Mason, who let in three more on 11 shots.