The win knocked Seattle into the No. 3 spot in the NFC.
Hasselbeck finished 18 of 27 passing, but also threw two interceptions for the Seahawks (10-5), who have won six of seven.
Shaun Alexander added 73 yards and one touchdown for Seattle.
Troy Smith was 16-of-33 passing with a touchdown pass for the Ravens (4-11), who have lost nine straight.
The 79-yard touchdown pass was caught by Derrick Mason with 4:41 remaining.