Bale was left out of Zidane's starting XI, the French coach preferring Karim Benzema and Isco in support of Cristiano Ronaldo, but he had a devastating impact from the bench.
Just two minutes and two seconds after his introduction for Isco, Bale scored one of the great Champions League final goals, sending a beauty of a bicycle kick flashing past Loris Karius.
And when the German goalkeeper fumbled Bale's rocket into his own goal, the forward became the first player to score twice from the bench in a Champions League or European Cup final.
Bale suggested in a post-match interview he will seek to leave Madrid if he is not given assurances over receiving more starts and Zidane accepted he could have played the former Tottenham winger more often.
"It's complicated but everyone looks at themselves. I get it," Zidane said. "This is a squad and it's not going to change.
"I try to do what's best for the team and every once in a while it's true that he deserves to play more.
"I understand who wants more minutes, Bale has made the difference. It's normal to want more regularity, I understand."
Victory in Kiev means Bale has collected four Champions League titles in five years with Madrid, with his overhead kick inevitably drawing comparisons to a volleyed strike by Zidane in the 2002 final against Bayer Leverkusen.
"I'm not going to say which one is better," Zidane said when asked to compare his goal to Bale's. "Goals for the history of the club.
"The last one is always the most important. I'll say Gareth's."