Huddersfield have been promoted after Sheffield United keeper Steve Simonsen missed the decisive penalty in an epic League One play-off final shoot-out.
After a goalless draw, Terriers keeper Alex Smithies, who had saved two spot-kicks, scored to make it 8-7 on penalties, before Simonsen blazed over.
Huddersfield had the best chances in open play with Danny Ward hitting the woodwork in the second half.
Simonsen pulled off two fine stops to deny Peter Clarke late in normal time.
For Huddersfield it was redemption after last year's 3-0 defeat by Peterborough at Old Trafford.
And chairman Dean Hoyle will feel his decision to sack manager Lee Clark and replace him with Simon Grayson in February was justified.
Sheffield United now face a second season in the third tier after their relegation in 2010-11 after 22 years in the top two flights.
The turning point of their season was the jailing of top scorer Ched Evans for rape in April. The 23-year-old had scored 35 goals for the Blades, who were four points clear of third-placed city rivals Wednesday with three games left, but dropped into the play-offs after failing to win any of their remaining matches.
The Blades started with Richard Cresswell up front on his own after the striker returned to the starting line-up following an injury-plagued month.
The 34-year-old was isolated but caused Huddersfield problems with his sheer strength and almost scored the opener 10 minutes in.
Clarke failed to deal with a long ball under pressure from Cresswell but recovered to block the striker's shot. Then moments later Cresswell found Stephen Quinn with his cross but the Irishman's header was blocked for a corner.
On a warm day at Wembley, with temperatures reaching 25C, clear-cut chances were few and far between. Both sets of players were taking the opportunity to get drinks at any break in play.
Neither side managed a proper shot on target in the first half but seconds after the break Ward almost scored the opening goal. The ball found the 20-year-old winger just outside the box and he hit the woodwork - just as he did in last season's final at 0-0.
It took the Terriers 82 minutes to test Simonsen in the Blades goal, but when they did, they had three shots on target in 60 seconds.
Clarke forced a brilliant save down low from the United keeper and, from the follow-up, Tommy Miller's shot was blocked on the line by Michael Doyle. And Simonsen again denied Terriers captain Clarke from the following corner.
The Blades brought on striker Chris Porter for Cresswell and he headed wide within seconds of his introduction.
Quinn fired just wide at the near post into the side-netting late on as the game went into extra time.
As in normal time, the extra 30 minutes did not provide a feast of action in the goalmouth, although Smithies was forced to pull off a fine stop from Quinn.
Huddersfield looked the better side going forward and substitute Alan Lee forced another good save from Simonsen in the 110th minute.
And 40-goal top scorer Jordan Rhodes almost had an empty net to tap into right at the end of the game but Nick Montgomery scooped the ball away from him at the last moments.
And so the game went to penalties.
Huddersfield missed their first three kicks, with Miller, Damien Johnson and Lee all failing to convert, while Lee Williamson and Matthew Lowton missed for the Blades either side of Neill Collins's successful kick.
Clarke then scored for the Terriers and Andy Taylor, brought on specifically for the shoot-out with seconds left, hit the post.
The next six takers for each side all scored their kicks before Smithies, who only played after first-choice Ian Bennett failed a late fitness test on a hand injury, became the Terriers' hero and Simonsen the villain for the Blades.
VIEWS FROM THE DRESSING ROOM
Huddersfield Town boss Simon Grayson:
"We never expected it to get down to the goalkeepers.
"There was nothing in the game whatsoever.
"What an unbelievable end to the game and I really feel for Sheffield United. Hopefully they can come up next year.
"The best way to get promoted is by winning at Wembley."
Sheffield United manager Danny Wilson told BBC Radio Sheffield:
"What was going to separate (the two sides) was maybe a little bit of magic or like you saw a penalty kick.
"To save the penalties like Steve did, who would have thought it would come down to that?
"He nearly got his hand to two others but that's the way it goes sometimes. I don't know if that's fate but for him to miss the penalty, it's blameless."