Vegas moved one point ahead of the Dallas Stars for the second wild card from the Western Conference.
The Golden Knights started with 11 forwards in the lineup but lost Keegan Kolesar to injury late in the first period. Defenseman Dylan Coghlan played forward the rest of the game.
"We're playing a guy short and Kolesar comes out in the first," Vegas coach Pete DeBoer said. "It feels like we haven't been able to get into a four-line rhythm because we will be short a body or two every night, but I thought we dug deep. I didn't like our first period. They came out with a little more fire. I thought [Logan Thompson] made some big saves in the first that allowed us to recognize that this was going to be a harder game than we thought."
Chris Driedger made 27 saves in his second straight start for the Kraken (21-40-6), who had won three of four.
"The second period is the difference in this hockey game," Seattle coach Dave Hakstol said. "It wasn't a shorthanded goal, but it was a turnover and we're right at the end of our power play. A couple of things that need to happen differently there to make sure that doesn't happen. … We didn't take care of the puck, so turnovers lead to transition, and transition is offense for them. It also led to a lot of O-zone time for them for some of their good players, and when they're in the O-zone, they got inside us."
Shea Theodore gave Vegas a 1-0 lead at 7:38 of the second period. After serving a high-sticking penalty, Theodore stepped out of the penalty box behind the Seattle defense. Jonas Rondbjerg intercepted a pass from Seattle forward Victor Rask and got the puck up to Theodore, who scored on a backhand over Driedger's glove side.
"Big, big goal," DeBoer said. "I think you guys have seen the first goal is a difference-maker for our group. Early in the season we were getting it all the time. We went through a stretch when we didn't get it at all and we're playing from behind every night. But it's tough for our group because we're not scoring easily, so a big goal for us."