After a patchy season for Real Madrid, Casillas had come under fire for a perceived lack of focus following the 1-0 defeat by Switzerland in their opening Group H match.
The presence in South Africa of the glamourous Sara Carbonero, who works for Spanish broadcaster Telecinco and conducts post-match interviews, was seen as a distraction but "Saint Iker" has silenced his critics in emphatic style.
Two years after leading Spain to glory at Euro 2008, the 29-year-old has become the Iberian nation's most successful captain, pulling off a string of vital saves in their run to the World Cup final, where Andres Iniesta's goal deep into extra time gave them a dramatic 1-0 win over Netherlands on Sunday.
"I am over the moon," he told reporters at the Soccer City stadium, moments after breaking down in an ecstatic mixture of tears and laughter at the final whistle and triumphantly lifting the gilded trophy.
"We have deserved this from start to finish," he added. "I want to thank everyone who has supported me."
Casillas has amassed 111 appearances for the national team since making his debut in June 2000 at the age of 19 and is closing in on fellow keeper Andoni Zubizarreta's record of 126.
He was awarded the "Golden Glove" prize for best goalkeeper in South Africa and it is tough to pick out the best, or most important, save he pulled off over Spain's seven matches.
DEFINING MOMENT
Arjen Robben had a chance to put the Dutch ahead when clean through on goal in the second half of the final but Casillas somehow got an outstretched foot to the winger's shot and the ball flew just past the post to safety.
The penalty save against Paraguay in the quarter-finals was a defining moment and the way his team mates sprinted across the pitch to celebrate with him at the final whistle was proof of the respect and affection in which he is held.
"I don't think that we really know what we have done tonight," Casillas said before the players flew home to Madrid straight after the match to join in the celebrations.
"We have achieved what every child dreams about, what until now we could only experience in video games, and it's a very special moment for us."
Casillas has come a long way since helping Spain win the under-20 World Cup in Nigeria in 1999, when current team mates Xavi and Carlos Marchena were also in the side.
As well as success on the international stage, he has won four La Liga titles and two Champions Leagues with Real and potentially has another decade left before retirement.
Casillas said the World Cup was for Carbonero and his family, as well as the millions of fans watching in Spain.
"I have been through a lot and I have had a lot of setbacks," he said."Sara has been having a really bad time these past few days so I dedicate this to her and my family."
