The Welsh forward, signed for 100 million euros from Tottenham Hotspur last August, headed his side in front with 10 minutes of extra time remaining as Real claimed their 10th European Cup in dramatic fashion.
Bale, the first Welshman to score in world football's most prestigious club final, had also netted a magnificent solo winner when Real beat arch-rivals Barcelona in the Spanish Cup final last month.
With so much expectation following his move from London, the 24-year-old struggled for form initially in the Spanish capital having arrived less than 100 percent fit after a protracted transfer saga spanning most of last summer.
He scored on his debut but it was not until October that he really began to spark, scoring twice in a 7-3 win over Sevilla.
Once into his stride there was no holding him back and the unassuming player who was nearly loaned out in his disappointing early years at Tottenham has already written his name into the folklore at the Bernabeu stadium.
Despite the mind-boggling amounts of money Bale cost Real, his joy could not be counted in cash terms on Saturday as he marked the biggest night of his career so far with a vital contribution despite missing earlier chances.
"For me the price tag means nothing," Bale, with a Real scarf wrapped around his head, told Sky Sports.
"If I came for a penny I wanted to play well and play in big competitions and win trophies like we have this season and obviously the move has paid off."
Bale's 23rd goal of the season for Real, an impressive return which included six in the Champions League, arrived just when the Lisbon final looked to be heading for penalties.
Angel di Maria's shot was well saved by Atletico keeper Thibaut Courtois but the ball looped up invitingly and Bale, arriving at the far post, stretched his neck muscles to head it into a gaping goal to spark wild celebrations from Real's fans.
"We have shown all season for us when we play our own football we win games. It was 'keep attacking', do what we do best, and we all believed in that," Bale said.
"I started to have a little feeling (it wasn't going to be my night) but I've learned to keep going, forget about chances missed and keep going and eventually one will come.
"Thankfully I got a decisive goal. I was just thinking do not miss it. The celebrations from the fans means everything for me. It was an unbelievable feeling lifting the trophy, one you can't describe and it will be a memory forever."
Real coach Carlo Ancelotti said Bale will be an even more formidable force next season.
"At the right moment, Gareth Bale was ready to score and that's how it's been all season," the Italian said.
"He'll be even better next year."
- Sports & Recreation
- Tottenham Hotspur