Kaepernick then was responsible for consecutive 22-yard gains, hitting Crabtree, then rushing to the Seattle 28. His fumble on the next play was recovered by center Jonathan Goodwin, who even lumbered for 2 yards.
Then, Doug Baldwin, who played for 49ers coach Jim Harbaugh at Stanford, stepped up -- and through San Francisco's coverage -- on a scintillating 69-yard kickoff return that made the stadium shake for the first time all day.
That set up Hauschka's 40-yard field goal. And a frantic finish.
Seattle took its first lead on Wilson's throw to Kearse with 13:44 left, and CenturyLink rocked again.
The place went silent soon after when Niners All-Pro linebacker NaVorro Bowman sustained an ugly left knee injury midway and was carted off. Bowman, who was having a huge game, had forced a fumble at the San Francisco 1, but Lynch recovered.
"I never heard him yell like that, or even stay down for a moment," teammate Patrick Willis said of Bowman.
Harbaugh said after the game it appeared Bowman suffered a torn ACL.
The Seahawks had gotten their first turnover moments earlier when Cliff Avril stripped Kaepernick and Michael Bennett recovered. But Lynch and Wilson botched a handoff on fourth down on the play after Bowman's injury.
It took only two plays for Chancellor to haul in Kaepernick's underthrow to Boldin, and Hauschka's 47-yarder ended the scoring.
But not the excitement.
Kaepernick, who rushed for 130 yards, got San Francisco to the Seattle 18 with his arm. But his pass for Crabtree was brilliantly tipped by Sherman to Smith.
"We knew it would come down to us in the back end to win this thing," Sherman said.
The final play was similar to last year's Super Bowl ending, when Kaepernick missed Crabtree in the end zone from the 5 and Baltimore survived.
"It's tough. Any time you get this close to the Super Bowl and lose, it's pretty upsetting," tight end Vernon Davis said. "We just didn't get it. We've been down this road before in the same kind of situation. It's hard."
Whether it was nerves or just a great play by Aldon Smith, Wilson fumbled on Seattle's first snap. Smith got credit for a sack and a recovery, too -- a defender's dream -- at the Seahawks 15.
More staunch defense followed, this time by Seattle, which held and only gave up Phil Dawson's 25-yard field goal.
Seattle simply had no answers for Kaepernick's runs, looking either flat-footed or plain-out lost when he took off. He gained 98 yards on the ground in the first half, including a 58-yard second-quarter run, the longest of his three-year career and the longest Seattle's defense allowed all season.
But he was less effective in the second half and was plagued by turnovers.
Wilson came up with a huge improvisation of his own moments after Kaepernick's long jaunt. Wilson avoided the rush with some nifty scrambling before spotting Baldwin behind the defense for a 51-yard pickup.
All it resulted in was Hauschka's 32-yard field goal, making it 10-3.
Baldwin finished with six receptions for 106 yards.
And now it's on to New Jersey, where Carroll once coached the Jets for a season. That didn't end well -- he was fired so the team could hire Rich Kotite. He heads back with a chance to add a Super Bowl crown to two national titles as coach at Southern California.
"It's quite a magical moment," Carroll said. "You can't really grasp the moment. Did we really do this?"
Yep -- the Seahawks and their 12th Man.
Information from The Associated Press was used in this report.