The Penguins did all their scoring in the middle period to win their fifth straight game. Washington has dropped three in a row and remained stuck on an Eastern Conference-low two victories.
Mike Ribeiro gave Washington a first-period lead, but Pittsburgh scored on the power play three times during its big second stanza.
Malkin tied it 6:59 into the period and Pascal Dupuis put the Penguins in front with 7:11 left on a slap shot.
Crosby finished the outburst with a power-play goal that came just 22 seconds from the end of the period.
Marc-Andre Fleury made 23 saves for Pittsburgh. Michael Neuvirth opened in goal for the Capitals and gave up two goals on 11 shots. Holtby surrendered three goals on 17 shots.