Seattle quarterback Russell Wilson shook off four interceptions to throw the game-winning 35-yard touchdown to Jermaine Kearse 3:19 into overtime.
After trailing 16-0 after two quarters, Seattle overcame the largest halftime deficit in a championship game in NFL history.
The Seahawks finally got on the scoreboard with just under five minutes to play in the third quarter thanks to a perfectly executed fake field goal. Holder Jon Ryan rolled left and lofted the ball to offensive tackle Garry Gilliam in the end zone.
A Mason Crosby field goal put Green Bay up 19-7 early in the fourth. Then with 2:09 left in the game, Wilson faked a hand off to running back Marshawn Lynch and ran in one-yard touchdown. Seattle recovered the ensuing onside kick, setting up a 24-yard touchdown run from Lynch to put Seattle up 22-19 with 1:25 to play.
But Aaron Rodgers led the Packers down the field, and Crosby sent the game into overtime with a 48-yard field goal. Rodgers threw just one touchdown and 178 yards and two interceptions of his own.
Seattle won the overtime coin toss and, six plays later, the ball game. On Feb. 1 they will try to become the first repeat Super Bowl champions since the New England Patriots won back-to-back titles in 2004 and 2005.