Jared McCann had a goal and an assist as Seattle (21-12-4) won its third straight.
Eeli Tolvanen opened the scoring for the Kraken on the power play, with Matty Beniers and Alex Wennberg also chipping in.
Martin Jones stopped 26 shots for the win in net.
John Tavares replied for Toronto (23-9-7) on the power play.
Goalie Matt Murray made 21 saves in his first start of 2023 for the Maple Leafs.
Despite Toronto dominating play for the first half of the game, even outshooting the Kraken 10-3 in the opening period, Seattle struck first.
Tolvanen wired a wrist shot from the point past an unobstructed Murray midway through the first with Toronto defenceman Morgan Rielly in the penalty box for cross-checking.
Tavares tied it up for the Maple Leafs on a power play nearly four minutes later. Mitch Marner sent a pass in on Seattle's net where Tavares and Michael Bunting were standing in front of Jones. Tavares deflected Marner's pass between his legs, past Bunting and Jones, and into the net.
Just 14 seconds later Dunn handcuffed Murray with a wrist shot that dropped to the ice off the Toronto goalie's arm and slid over the goal line to once again give the Kraken a one-goal lead.
A streaking McCann made it 3-1 shortly afterward, taking a lead pass from Jaden Schwartz for a clean breakaway. He snapped a shot past Murray, pumping his fist as he curled away past the goal. It was McCann's team-leading 18th goal of the season.
Beniers piled on as the second period wound down, pivoting sharply with the puck on his stick near the faceoff circle and whipping a shot past Murray.
It took less than three minutes of play in the third period for the Kraken to add to their lead. Wennberg completed his partial breakaway with the puck on his backhand and slid it past Murray.
Like McCann, Dunn and Beniers's goals, it came at even strength, adding to Seattle's league-leading 5-on-5 scoring rate.
MARNER ALL-STAR — Marner was named to his third consecutive all-star team on Thursday night. The 25-year-old Toronto forward from nearby Thornhill, Ont., is on pace for a career season with 44 points (14 goals, 30 assists) through 39 games.
SAMMY BREAK — Murray got the start over Ilya Samsonov in Toronto's net after the 25-year-old Russian goaltender let in five goals on 32 shots in the Maple Leafs' 6-5 shootout loss to St. Louis on Tuesday. Although Samsonov has a 2.38 goals-against average on the season, he has struggled in his last four games, allowing a total of 17 goals in that span with a 2-1-1 record. Murray has given up 13 goals in his past five games, with a 3-2-0 record.
UP NEXT — Toronto will close out its three-game homestand on Saturday when the Detroit Red Wings come to Scotiabank Arena. The Maple Leafs have 10 of their 14 games in January at home. Detroit has back-to-back games this weekend, hosting the Florida Panthers before making the trip to Toronto.
This report by The Canadian Press was first published Jan. 5, 2023.
John Chidley-Hill, The Canadian Press