Matty Beniers, Eeli Tolvanen and Vince Dunn each had a goal and an assist, and Yanni Gourde had two assists for the Kraken (23-12-4), who have won the first four games of a seven-game road trip.
"We had a great start to the game," Seattle coach Dave Hakstol said. "We played a really good first period. You know the way that you want to come out on the road, and we were able to not only build the lead, but we played a really good first period, so that set us up."
Sam Montembeault made 37 saves for the Canadiens (16-22-3), who were coming off a 5-4 win against the St. Louis Blues on Saturday but have lost eight of nine (1-7-1).
"After a big win like that, I don't know, we seemed to take it really easy, thought it might be an easy night," Montreal captain Nick Suzuki said. "And there are no easy nights in this league, especially with a team like that, a lot of guys playing to prove something, and they've been playing really well as of late. We just dug ourselves too big a hole in the first period."
Tolvanen gave the Kraken a 1-0 lead at 6:54 of the first period, one-timing a pass from Dunn glove side from the right edge of the crease.
"I think for me and [Tolvanen], we find each other," Dunn said. "You know when I give him the puck, I just tell him to shoot. He's got a great shot, so he's making my life look easy."