As you squinted your eyes in the dazzling sunshine that bathed the Gleneagles Hotel yesterday while the amiable Irishman trotted up its front steps, it almost looked like you were staring at a walking wall of gleaming tooth enamel. Whether Team USA will wipe the beam from his face when the transatlantic tussle comes to Perthshire in 19 months remains to be seen, but, for the time being, McGinley will continue to play the role of a Cheshire cat in an industrial cream factory.
"Coming here now is a huge moment in my career," said McGinley, who made a quick stop-off at Bute House in Edinburgh where he was presented with a replica of an 1880, maple-headed putter by the First Minister Alex Salmond.
"Now, irrespective of what the result is, this will be a place that is synonymous with me for the rest of my life. Just as The Belfry has become, in terms of me holing that winning putt [in 2002], I can feel that sense of connection between me and here forever more."
It's been six weeks now since McGinley was entrusted with the captain's armband for the 2014 match over the PGA Centenary course and the 46-year-old Dubliner has already noticed the changes in his everyday existence. This is a man who has been immersed in the Ryder Cup since making that memorable debut in 2002.
Two more winning appearances as a player and a further two as a trusted, valued and highly respected vice-captain have given him the kind of insights usually reserved for a keyhole surgeon. Despite his past experiences and the relentless note taking that has helped him cobble together an intricate dossier on the biennial bout, McGinley's appointment as captain has been something of an eye-opener for him.He is well aware that the Ryder Cup is a leviathan of an event but now he is seeing the sheer scale of the contest from a different perspective.
"I think my life has changed already," admitted the four-time European Tour winner as he prepared for his first reconnaissance mission of Gleneagles since taking up his new post. "Every night, I go to bed thinking about the Ryder Cup and every morning I wake up still thinking about it. There is no doubt that my profile and the level of interest that people have in me has escalated quite significantly.
"That's all part of the job, I understood that was going to happen but it has still taken me aback how grand the scale of it is. I already knew how it worked inside the ropes but now that I'm seeing the grand scale of what a Ryder Cup is and what goes into its organisation, it's incredible.
"Someone told me that more than 500 million people watched the press conference when I was announced as captain. That puts it in scale.
"I mean, you are talking about 250 million watching Real Madrid v Manchester United and then when you compare it to that announcement, it shows where the Ryder Cup is in perspective of world sport. If that wasn't a wake-up call, I don't think anything would be."
While McGinley won't be rushed into naming his backroom team – "I will have four vice-captains but it will probably be the middle of next summer before I announce them" – he has always expressed a desire to give this Scottish showpiece a distinctly tartan hue.
He doesn't have to look too far for key ingredients. Sam Torrance, the Largs legend who led Europe in 2002, left a lasting impression on McGinley as an inspirational man-manager and the Scotsman's knowledge of Ryder Cup warfare will be a valuable weapon in the latest captain's armoury.
"At this moment, I have 20 to 25 people who could potentially be very good vice captains," he said. "Whether Sam is a vice captain or not, he will certainly be someone I'll be seeking a lot of counsel from because I've learned an awful lot from him. He was my first captain so I'm probably going to learn more from him than anybody else.
"I have plenty of my own ideas but at the same time I don't have a massive ego to think 'oh he's a bigger personality than me, I don't want him to be a vice captain because then he'll overshadow me'. This is about winning the Ryder Cup and having people in the room that the players are going to be comfortable with."
When McGinley made the last of his three successful cup campaigns as a player, on his own turf at the K Club in 2006, he was one of three Irishman in Ian Woosnam's side, a trinity made up by Padraig Harrington and Darren Clarke.
With four Scots, Paul Lawrie, Richie Ramsay, Stephen Gallacher and Scott Jamieson, all inside the top 70 of the world rankings, there is genuine optimism that the Gleneagles gathering will feature at least one home representative on the playing front and McGinley has urged the foot soldiers to show their true colours and mount a concerted assault.
"I would love nothing more than to have at least one Scot in the team," said McGinley, who won the Scottish Youths' Open as an amateur at Ladybank, 25 years ago. "When we played in Ireland in 2006, a quarter of the team were Irish so that's the challenge now for the Scottish, to get 25% of the team from the home country."
If that happened, it wouldn't just be the smiling McGinley who'd be grinning from ear to ear.