At Pebble Beach, the 30-year-old Ulsterman took a couple of seconds out from winning the tournament to extend Happy Father's Day greetings to the watching world.
After fighting all the way down the back nine to his first Major victory on Sunday, surely seven minutes with Leno in front of a live audience in a TV studio would be a breeze — and that's exactly how it looked.
Then he and the US Open trophy were whisked across Los Angeles, with a police escort no less, to Beverly Hills and the set of the hit TV show ‘Entourage'.
Along with meeting the cast and crew of his favourite TV show, McDowell also got to do a little acting himself, speaking a couple of lines as he made a cameo appearance in the final episode of the series.
The Irishman brought a few 18th-hole flags with him as gifts, signing them: “Thanks for letting my entourage meet your Entourage - Graeme McDowell.”
In between rehearsals and takes, they exchanged autographs and posed for pictures with the trophy.
“It was great craic, hilarious. Everyone at the shoot was as delighted to meet Graeme as he was to meet them,” said McDowell's agent Conor Ridge, founder of Dublin sports management company Horizon, who'd set up the ‘Entourage' appearance with a friend on the show's production staff.
“Profile-wise, this is really great for Graeme,” added Ridge.
Put up for the night at the exclusive Beverly Hills Hotel, staff kept the restaurant open late so McDowell, his father Kenny and Ridge could have dinner. As they sat at the table, alone in each other's company for the first time since Sunday afternoon, McDowell simply shook his head and said “wow”.
“You know, I think that was the first time he'd had an opportunity to let all that's happened sink in. This really is fantastic,” said Ridge.
McDowell, who flies to Belfast today, revealed that beneath his calm exterior during Sunday's march to victory, he'd found the experience so nerve-wracking he couldn't wait for it to end.
“It was a hard day,” he explained. “I said to Kenny (Comboy, his caddie) at one point when I was walking up 13, ‘Is it bad counting down the holes because I want this to be over?'.
“And Kenny said, ‘I've been doing the same thing for the past nine holes.' You dream of one day being in that position. But when you're actually in that position, it's scary and you want it to be over.”
McDowell is proud that he hit his best golf shots of the week amid the emotional whirl of those final few holes.
The first time he had looked at a leaderboard in the last round was on 11, “because I'd just bogeyed nine and 10 and was feeling like I needed something to spark me”, he said. “I saw I was two clear and just drove myself at that point to really dig in.
“You can't get ahead of yourself. You think about picking the trophy up, you dream about picking that trophy up, but you've got to stay right in the present out there because there are so many tough shots to come.
“There were so many names popping into my head. I thought of Padraig Harrington. I thought of Zach Johnson, YE Yang and Lucas Glover, Trevor Immelman, all these guys who won Majors for the first time. I thought, ‘they could do it, so can I'.”
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