The Lancashire outfit have been out of the top flight since 1971 but they showed remarkable character to twice come from behind to lead 3-2 at the break and clinch a place in the Premier League estimated to be worth £90million.
Michael Chopra put Cardiff ahead but Charlie Adam levelled with a free-kick for his 19th goal of the season before Joe Ledley restored the Welsh club's advantage with a neat finish.
Yet the energy and desire that has been so evident in Ian Holloway's side throughout the campaign again came to the fore as Gary Taylor-Fletcher and Brett Ormerod struck from close range shortly before the break to put Blackpool in front.
Ormerod's 13th goal of the season - undoubtedly the most important strike of the 33-year-old's long career - gave the Seasiders an advantage they did not surrender.
And it ensured the Blackpool supporters - who made one half of Wembley a sea of brilliant orange - were in ecstasy at the final whistle while Cardiff boss Dave Jones and his players were left devastated.
Blackpool - whose average home crowd of 8,611 was the second-lowest in the Championship this season - will be the smallest club in the top flight since the formation of the Premier League.
They will rub shoulders with the likes of North-West neighbours Liverpool and Manchester United next season and will probably be tipped by most pundits to finish bottom.
Yet there is an energy about Blackpool that has been evident since Holloway, 47, arrived last summer and breathed life into the club.
When the charismatic Bristolian was appointed, Blackpool were rated among the favourites for relegation to League One after struggling badly during the previous campaign but they deserved their victory after defending like demons in the second half.
Cardiff fashioned the first goalscoring opportunity inside the fourth minute. A fine left-wing cross from Peter Whittingham was fired on to the angle of post and bar by Chopra, though the respite for the Seasiders was to prove short-lived.
In the ninth minute, Whittingham collected possession midway inside the Blackpool half before finding Chopra with an excellent slide-rule pass that allowed the former Newcastle striker to beat the offside trap.
Chopra struck a fierce first-time right-foot shot into the bottom left corner to give Blackpool goalkeeper Matt Gilks no chance whatsoever.
Yet Holloway has fashioned a side with guts and his men drew level within four minutes of falling behind.
Cardiff midfielder Stephen McPhail clumsily handled the ball 25 yards from goal and Adam stepped up to curl a delightful free-kick past David Marshall and into the top right corner.
The Bluebirds were dealt another heavy blow two minutes later when striker Jay Bothroyd succumbed to injury and was replaced by Kelvin Etuhu.
However, Cardiff were back in front seven minutes before the break and Whittingham was again the architect of the goal.
He showed outstanding vision to spot Ledley making tracks behind the Blackpool defence and another perfect pass was clipped home left-footed from a tight angle by the Wales international.
Remarkably, Blackpool were level again three minutes later after Taylor-Fletcher volleyed against the outside of a post from 18 yards.
Cardiff cleared the ball for a corner and after defender Ian Evatt saw his shot cleared off the line by a Bluebirds defender, Taylor-Fletcher headed home from just two yards out.
And they forged ahead for the first time in the first minute of added time when DJ Campbell caused havoc inside the Cardiff penalty area and Ormerod rifled home the loose ball from eight yards.
Cardiff defender Darcy Blake had an effort ruled out for offside on the stroke of half-time and the Bluebirds' luck was out again in the 57th minute when Chopra's 20-yard strike hit the crossbar.
Cardiff brought on Ross McCormack for the ineffectual Chris Burke moments later and Ledley then headed a corner from Whittingham wide at the far post.
The Bluebirds continued to probe and Etuhu burst clear in the 64th minute only to fire straight at Gilks.
With 14 minutes remaining, Chopra headed just wide and McCormack fired into the sidenetting moments later as Blackpool held on for a famous and profitable victory.