The Tangerines won 3-2, with all the goals coming during an opening half of unbelievable excitement and occasionally awful defending.
Michael Chopra and Joe Ledley twice put Cardiff ahead with crisp strikes but a Charlie Adam free-kick and a close-range finish from Gary Taylor-Fletcher drew the Lancashire side level on each occasion - before Brett Ormerod struck the winner shortly before the interval with a low strike.
The result completes a remarkable season for Blackpool, who can now plan for the top-flight for the first time since the 1970-71 campaign.
Adam 13 Chopra 9
Taylor-Fletcher 41 Ledley 37