The quietly spoken Welshman is an unlikely hero but a Lions Test record 21 points and assists for the two second-half tries that broke the back of the Wallabies were integral to the first Test series triumph for the tourists since 1997.
The 24-year-old's 49 points over the three Tests was another record - beating the 41 his kicking coach Neil Jenkins scored in South Africa 16 years ago - and helped earn him the Player-of-the-Series award.
"It feels incredible," he told reporters. "It's all worth it at the end of the day.
"As a kid you just dream of putting on the Lions jersey. You look at the guys from '97 and the guys who won that. It's amazing to be part of a Lions series win."
Despite his near-flawless place kicking throughout the tour, though, Halfpenny admitted it had taken him a couple of days to get over the miss from the halfway line that denied the Lions the series win in Melbourne last week.
"It was pretty hard after the game, it was tough. I was just devastated really," he said.
"I'm quite hard on myself, I hate missing kicks. I wanted to be part of a Lions series win and I worked harder and harder in training over the last couple of days.
"It stayed with me for a couple of days, it was tough to pick myself up but we were lucky we had a second chance.
"You don't often get a second chance."
He certainly did not waste it, converting three of the four tries and punishing the Australians for their frequent infractions at the scrum with five penalties.
The 21-point haul beat the 20 scored by Jonny Wilkinson against Argentina in 2005 and Stephen Jones in the second Test against South Africa in 2009.
Halfpenny said he had practised longer kicks this week and the significance of a successful penalty attempt from halfway that gave the Lions a 10-0 lead after 10 minutes was not lost on his captain Alun Wyn Jones.
"We knew Australia would know if obviously he gets it from the 50, then anywhere in that grey zone in the middle part of the field, they'd have to be pretty much whiter than white in the contact," the lock said.
"And that enabled us to get a bit more of a foothold at the breakdown."
Halfpenny missed the visit of James Bond actor Daniel Craig to the Lions dressing room, preferring to catch up with some friends from his home town of Gorseinon out on the pitch.
A self-confessed perfectionist, even among the celebrations of a small moment of sporting history, Halfpenny was still thinking about the one that got away - the conversion of the George North try his own counter-attack set up.
"I came round it a bit, I could feel the wind coming left to right so I tried to put it left but put it a bit too much left," he said.