Alex Ovechkin scored and had two assists, and Vitek Vanecek made 29 saves for the Capitals (30-18-9), who have won two straight after losing three in a row. Ovechkin, with 764 NHL goals, is two from tying Jaromir Jagr for third in history.
"I'm not going to lie, it's more fun to win, especially on home ice, so no complaints there," Washington forward Tom Wilson said. "It was a fun game. The building was loud. We were a little slow to start but we found our feet and guys pulled together and a win's a win."
Joonas Donskoi and Colin Blackwell scored for the Kraken (17-35-5), who have lost eight of nine. Chris Driedger made 20 saves, and defenseman Mark Giordano played 20:51 with two shots on goal in his 1,000th NHL game.
Washington was 2-for-2 on the power play, Seattle was 0-for-3.
"We didn't get enough in the first two (power plays)," Kraken coach Dave Hakstol said. "The third period, we had some looks and a little bit of volume, but we weren't able to generate anything that was real dangerous. They won the specialty teams tonight and, scorewise, that was the difference in the game."
Sheary gave the Capitals a 3-2 lead at 11:48 of the second period when he scored off the rebound of Wilson's shot on a power play.