The combative Argentine has transformed Atletico since taking over midway through last season and the 2-1 comeback triumph, made all the sweeter as it was at Real's Bernabeu arena, was their first success against their vastly wealthier and more prestigious neighbours in 14 years.
Fans were already dancing and singing at the Neptune fountain in central Madrid, the traditional site of Atletico celebrations, in the early hours of Saturday morning and a huge party is planned there in the early evening after the players tour the city in an open-top bus.
Once described as "playing with a knife between his teeth", Simeone was in the Atletico side when they last won the Copa in 1996, beating Barcelona 1-0 in Zaragoza.
That success pales when compared with Friday's achievement against a team containing more than 400 million euros worth of talent and playing at their own stadium.
An inspirational leader who wears his heart on his sleeve, Simeone has brought steel to the squad while getting the best from players like Colombia forward Radamel Falcao and his strike partner Diego Costa of Brazil.
Belgium goalkeeper Thibaut Courtois, who is on loan from Chelsea, has also flourished and made two brilliant, point-blank saves late in the game to deny Gonzalo Higuain and Mesut Ozil.
"Winning at the Bernabeu after falling behind against a super powerful team speaks marvelously of a unit that has humility, that knows what it can do and is not afraid to do it," Simeone told a post-match news conference.
"We can't appreciate it now but this victory will be remembered for a long time," added the 43-year-old.
"People have suffered, people have worked hard and now more and more kids will grow up Atletico fans. I invite everyone to come down to Neptune wearing the shirt."
Beating Real to win Spain's domestic cup was even sweeter than last year's Europa League success or Atletico's subsequent victory against Chelsea in the European Super Cup, Simeone said.
"This victory is special," he said. "All the titles were really nice but this one will remain in my mind and that of all the fans."
Winning the cup capped a superb season for Atletico and they are assured of third place and a lucrative return to the Champions League.
That may help them hold on to players like Falcao who are coveted by richer rivals, although it would not be a surprise if Atletico cashed in on the player known as "the tiger".
For now, Simeone and the players are focusing on celebrating a first win against Real since 1999.
"The team gave everything on the pitch and it is incredible to have beaten this Real Madrid," captain Gabi told reporters.
"Nobody gave us a hope," added the central midfielder, who was shown a second yellow card and sent off for time wasting in the dying minutes.
"We knew that we were strong, it was a mental thing, and we were determined to win the final."
If Atletico manage to hang on to their top performers and Courtois is allowed to stay they will likely be challenging for more silverware again next season.
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