Chris Carson added 46 yards on eight carries as well as Seattle's first-team offense amassed 273 total yards before its starters mostly checked out for the night.
The Chiefs marched 63 yards on 14 plays on their opening possession only to have the drive stall out inside Seattle's 20-yard line. Kareem Hunt was stopped by K.J. Wright for a 4-yard loss on third-and-1 at the Seattle 8-yard line to force a 30-yard field goal from Sam Ficken. Alex Smith completed just 7 of 17 passes for 44 yards before leaving the game.
The drive ultimately proved even more costly for the Chiefs as running back Spencer Ware left the game on a cart with a knee injury and did not return. He was injured on a six-yard reception late in the drive as Terence Garvin made the tackle.
After a pair of Blair Walsh field goals, Wilson connected with fullback Tre Madden for a 2-yard touchdown to give the Seahawks a 13-3 lead.
De'Anthony Thomas returned the ensuing kickoff 95 yards for a touchdown to close the deficit to 13-10. It was the Chiefs' only touchdown of the night.
Walsh would add two more field goals to extend the lead to 19-10 early in the third quarter.
First-round pick Patrick Mahomes led the Chiefs on a 74-yard drive that resulted in a 32-yard field goal by Ficken to trim Seattle's lead to 19-13. Mahomes was 8 of 15 for 70 yards in his limited action.
The Seahawks added another touchdown in the fourth quarter as Austin Davis connected with Tanner McEvoy for a 28-yard score. Backup quarterback Trevone Boykin posted a 0.0 passer rating, going 0 for 6 with an interception.