The Flames gave up three draft picks: a second-round (2022), third-round (2023) and seventh-round (2024) picks for the Swede.
The Kraken are retaining half of Jarnkrok’s $2-million salary-cap hit for the rest of the season.
Järnkrok, a native of Gavle, Sweden has 12 goals and 14 assists for 26 points this season with the Kraken, and helps Calgary’s chances of making an extended through the Western Conference.
“I want to thank Calle for everything he did for the Seattle Kraken, and we wish him all the best in Calgary,” Kraken general manager Ron Francis said.
The 30-year-old forward played eight seasons with the Nashville Predators before joining Seattle, totalling 94 goals and 117 assists over 508 games.
Järnkrok was drafted by the Predators in the second round (51st overall) in the 2010 NHL Draft.
The Flames announced the deal a couple of hours before taking the ice against the visiting New Jersey Devils.
Seattle also is expected to trade captain Mark Giordano, and forwards Marcus Johansson and Riley Sheahan before the NHL trade deadline Monday. Giordano was held out of the lineup for the Kraken’s game Wednesday night against Tampa Bay to prevent him from getting injured.
— With files from The Associated Press.