He kissed his wife, Hollywood actress Ashley Judd, then threw his arms around Susie Wheldon, whose husband Dan won last year's Indy 500 before he was killed five months later in a horrific crash in Las Vegas.
Franchitti put on a pair of white-framed sunglasses, the same that Wheldon used to wear, then dedicated his win to his fallen friend.
"To be on either side of Dan, that means more to me than anything," Franchitti said.
The Scotsman indulged in all the traditional winner's celebrations. He got his knees and kissed the bricks and guzzled some milk before tipping the bottle on his head.
The crowds applauded and he broke into a smile, knowing Wheldon would have approved.
"Vegas last year was the lowest of the low but the reason we all got back in the cars, the reason the mechanics got back in pit lane, the reason why the fans came back to the races, is the emotion of days like today," he said.
"That's certainly why I got back in the car and there's not a feeling like standing in Victory Lane."
It was a bittersweet moment for Franchitti, now one of just 10 drivers to win at least three Indy 500s. His team mate, Scott Dixon, finished second and Brazil's Tony Kanaan was third.
The three were all good friends with Wheldon. But while Franchitti enjoyed the spoils of victory, his friends had to console themselves with agonising close finishes.
"Actually it was good for Dan," said Kanaan, the only one of the four not to have won the Indy 500.
"Wherever he is right now, I think he's extremely happy. His three best friends in the top three."
Franchitti, who previously won in 2007 and 2010, produced a masterful drive to win on Sunday.
His race almost came unstuck almost as soon as it began when he was hit in pit lane by EJ Viso. His car was damaged and needed a new nose cone but he was able to rejoin the race, albeit from the back.
But he steadily worked his way through the field to put himself in contention to win when the race was reduced to a six-lap sprint after another yellow caution flag.
On the last lap, Franchitti was under pressure from Japan's Takuma Sato, who had also weaved his way through the pack, but got a lucky break when Sato crashed, attempting a risky overtaking move on the tricky first turn.
"He's very aggressive and that was his chance. I think he did everything right up until he lost the rear-end," said Franchitti.
"He made a good move. I wasn't very happy about it. But I didn't touch him, I didn't squeeze him down. He just lost the rear of his car."
Franchitti's win elevated him among the greats of American oval racing although he remains reluctant to talk about his success.
He has already won four IndyCar championships and only A.J.
Foyt, Al Unser and Rick Mears, with four wins each, have been more successful in America's greatest motor race.
"I don't come here with any expectations. I just go out and do the best job I can," he said.
"I don't go into races thinking I'm going to win this one.
You've got to let the race come to you. That's what I do."