Justin Forsett gained 67 yards and rushed for a score on 10 carries, while Marshawn Lynch added 44 yards and a touchdown on 17 totes for the Seahawks (3-2), who were coming off a bye week that followed a 20-3 defeat at St. Louis.
Mike Williams posted game-highs of 10 receptions for 123 yards and Deon Butler recorded a 22-yard TD catch for Seattle, which registered its first road win of 2010.
"I really think we waited too long to get one (a road win)," said Seattle head coach Pete Carroll. "We wanted all the guys to answer the call and play well in all three phases of the game. We had six sacks, knocked the quarterback around all day long, and we were able to run the football today."
Seattle went up 23-13 three plays into fourth quarter after a one-yard run from Lynch to cap a 92-yard drive, then the Bears had an 89-yard kickoff return for a touchdown by Danieal Manning negated due to a holding penalty.
Both clubs traded three straight possessions each without much offense. Chicago wasted its third drive in the series of futility when Robbie Gould missed a 54-yard try.
However, after Seattle went three-and-out on the next series, Hester took a punt 89 yards for a 23-20 game with 1:54 remaining. The onside kick was hauled in by a Seahawks special teamer on Chicago's 42, and Hasselbeck worked off the remaining time with three kneels.
"You have to be ready each week to play your best ball, and we didn't play our best ball today," said Bears head coach Lovie Smith. "If you can't convert offensively and let them convert and not get takeaways, it'll be a tough day."
Chicago struck on the first possession of the game, helped by a defensive pass interference call on Seattle which set up the Bears on the visitors' 22. Cutler hit Forte for a 13-yard gain, then a three-yard rush preceded his six- yard touchdown run.
Seattle responded on its first drive on a Hasselbeck pass to Butler for a 22- yard score, then moved ahead 14-7 early in the second on Forsett's nine-yard scamper.
A 34-yard make from Gould on the ensuing possession brought the Bears within four, and his 24-yarder with 1:10 on the clock made it 14-13 at the half.
Cutler was brought down by Jordan Babineaux in the end zone on the Bears' first drive of the third quarter, and though the Seahawks failed to capitalize, they kept that slim edge heading into the fourth after halting a pair of successive Chicago drives.
Seattle has won eight of 13 meetings with Chicago, including two of the last three matchups...The Bears listed linebacker Lance Briggs as inactive with an ankle issue that kept him out of practice all week, and guard Roberto Garza was absent following knee surgery...Safety Major Wright also missed his fourth straight week with a hamstring issue...The Seahawks listed defensive tackle Brandon Mebane as inactive with a calf injury that was aggravated in practice...Forte ended with 11 yards on eight carries and three catches for 40 yards...The Seahawks racked up 353 yards of total offense to 307 for the Bears...Seattle punter Jon Ryan suffered injured ribs during Hester's TD run in the fourth quarter, and cornerback Kelly Jennings left the game with a hamstring issue.