He's come close three times in the past only to have the championship snatched away from him at the last second, but finally this weekend at Auto Club Speedway in Fontana, California the 33-year-old from Toowoomba in Australia realised his long-held ambition to be crowned Verizon IndyCar Series champion.
"It's just surreal man. I can't believe it," admitted Power, who was previously runner-up in 2010, 2011 and 2012 only to see the title go to Dario Franchitti, Ryan Hunter-Reay and Scott Dixon in turn.
"It hasn't sunk in that I've actually finally won the championship," continued a dazed Power after the final IndyCar race of 2014. "That is unbelievable. That is 15 years of hard work. I started taking it seriously in 2000 and it's just been 15 years of hard work."
Power came into the weekend with a 51 point lead over his closest rival (and Penske Racing team mate) Hello Castroneves, but with double points on offer the championship battle could still have gone against him as he knew all too well from his past campaigns. At one point Castroneves was out in the lead and Power was in seventh place meaning there was just one point in it between them in the title fight.
"That was one of the hardest races ever. I was crying over the line and it just went on and on," Power admitted. "I was just so mentally exhausted. My hands were like so numb from holding the wheel so tight and I wanted to be a lot more. Its over and I want to be so much more but sorry, I am just so drained that I can't. I can't believe I won it."
The crucial moment came on lap 220 when Castroneves was handed a drive-thru penalty for failing to stay below the pit lane blend line on his final pit stop. That put the Brazilian off the lead lap and ended his hopes of overhauling Power, who could now afford to take his foot off the gas and cruise - relatively speaking - to the finish line in ninth place.
"Just being conservative when Helio [got his penalty]," said Power, confirming his late race decline in pace hadn't been due to any issue with the car. "Just taking it easy."
Power admitted to have felt the stress over the last fortnight: "Just was two weeks of not much sleep and stress and all that sort of stuff. Keeping my wife up at night. And just when I got in that race car just kept my mind on the job, focused and this is the result."
As for his future plans, Power already has his sights et on defending his brand new championship next year when the 2015 season gets underway in seven months time. The idea of moving to a different series - possibly even Formula 1 - is not a serious consideration for him, Power insisted.
"F1 is not realistic for me at my age," he said. "And to me IndyCar racing is the best racing in the world. I don't think you see close, more competitive racing anywhere especially for open wheel cars. I love racing IndyCar, and it's a very good group of teams and drivers right now."
For Penske Racing as a whole it's only the second time this century that they've successfully claimed the IndyCar Series title - something of an underperformance compared with six titles for Chip Ganassi Racing and four for the Andretti team over the same period, so it was no surprise that team owner Roger Penske was delighted with the outcome of the 2014 season.
"No question that Will deserves this championship," said Penske. "He deserves it. He was obviously the best road racer, won that championship a number of times. To see him operate on the oval this year, the way he ran at Milwaukee showed me what he's got.
"He won a number of races, a lot of poles and really brought some momentum to the team. I think his working with Helio and obviously bringing Juan on this year made us that much stronger," Penske added. "For me and from the team perspective, it was a big win and obviously for Will it's something that he's worked hard. I think he's got the monkey off his back now.
"Before the race, the entire team said, look, one is only going to win here tonight but it's a team effort, and it was all of us and everyone had something to do with the championship," he continued. "And obviously Will gets the championship ring for winning it. [But] to me it's something that Helio had a big part of and also Montoya - you can see how hard he ran tonight.
"Having that kind of stable of drivers is going to give us some great opportunity in the future," Penske summed up.