The Tasmanian finished just 0:58 of a second behind Tom Dumoulin (57:16:30) the fastest rider at the finish on Stage 20 before Tadej Pogačar smashed everyone out of the water, ripping the yellow jersey off Primož Roglič's back with a time of 55:55.
As Pogačar's Tour de France career is just starting with a bang, winning the yellow jersey on debut, Porte is in the twilight of his, satisfied with a podium in Paris.
"It's been many years of disappointment, crashes and whatever, dramas," Porte said.
“For me, it’s an absolute dream. I grew up watching the Tour on the other side of the world, seeing guys like Robbie McEwen, Cadel Evans, and Brad McGee. To finally crack the podium here is an absolutely incredible feeling.
"I'm just over the moon, it feels like a victory to me to be third."
"Now I can retire happy, this means everything to me."
Porte's blistering ride, the third fastest of the day, was 35 seconds quicker than Roglič's and 10 seconds better than Wout van Aert who was also on a tear.
In third place overnight, Miguel Ángel López was not even a factor, losing over five minutes to the Australian. But it was nothing compared to Pogačar's ride which Porte said was 'incredible.'
"Pogačar is a huge champion," Porte said. "It's going to be interesting with Bernal next year, they're the future of the sport it's going to be a fantastic tussle."
And as the 2020 Tour de France champion celebrates his 22nd birthday on Monday by waking up in Paris with the yellow, polka dot and white jerseys on his shoulders, Porte will head home to mark another birth.
"I'm just looking forward to rolling into Paris tomorrow and then getting home and meeting my daughter that's probably the biggest victory of them all."
It is Porte's last Tour de France as a GC leader, his new team next year not yet officially announced.
He has already accrued a place in Australian cycling history as one of the country's premier riders with multiple prestigious stage race victories, 5th overall at the 2016 Tour de France and 7th overall at the 2010 Giro d’Italia. Now he finally adds a Paris podium.
"In the lockdown I didn't think this race was going to happen and then me being me with the timing to miss the birth of my second child.
"My wife said to me come to the race and do your best and if she sees me at the back of the peloton sulking she would be upset with me."
"To come here, be third it's a massive sacfrice maybe the biggest one to miss the birth of a child.
"But this is sweet, this is a photo I'll have on the wall when I retire on the podium in the Tour."
And he is happy to serve once more as a domestique.
"There's no secret I'll be leaving Trek-Segafredo, but the way they've gotten around me has been fantastic. To come away with the podium the team's been fantastic. I had the world champion as my bodyguard."
"I'm 35, I don't want the stress anymore I'd like to go and help younger guys."
Don't miss out on the Porte podium party and Caleb Ewan contesting the sprint victory on the Champs-Élysées, the final stage of the 2020 Tour de France. Watch on SBS HD and SBS On Demand from 11:30pm AEST and the SBS ŠKODA Tour Tracker from 11:35pm AEST.