He paused for a moment, not wishing to let go, then rubbed the wood panel as if saying goodbye.
Finally he relinquished his grip and fell into the arms of his wife Michaela's heartbroken father Mickey Harte as they watched the remains of their special girl placed into the hearse and taken onward toward St Malachy's chapel.
Two weeks ago he was waiting for her inside the church as she made the same short journey from the Harte family home on the Glencull Road.
Today they went together. And behind them, not the chatter of excited wedding guests but the solemn hush made only by a sea of mourners.
At one point pupils from Glencull Primary School, where Mrs McAreavey went as a child, emerged from class to form their own miniature guard of honour.
The Gaelic Athletic Association may be the governing body of an amateur sport, but its part in organising the funeral was professional in every way - never more evident as the cortege made its way slowly along the A5 carriageway, one of Northern Ireland's main arterial routes closed to accommodate the event.
On one side of the colossal crowd walked Mickey Harte's Tyrone team, on the other players from his home town club Errigal Ciaran. Their respective red and blue tracksuit tops like two coloured ribbons bordering the black tide crawling down the hill.
"The GAA always take care of their own," one of the 500 GAA volunteers observed.
Outside the church too it looked like this was an event weeks if not months in the planning.
A marquee to hold 400 extra mourners, two huge TVs for the thousands more standing outside, and even a row of portable toilets - proof that everything had been thought of. Most were donated free of charge from within the GAA family.
It should have been warmer than the bright January sun suggested. But the frost glinting on the cattle-rutted fields surrounding St Malachy's betrayed a bitter chill in the air.
Mrs McAreavey was a teacher aged just 27. This ensured a congregation distinct by its youth. Pupils from St Patrick's Academy in Dungannon where she taught stood in silence among the young couple's friends and relatives, the only sound the constant babble of a nearby stream.
You can leave of messages of condolence to the Harte and McAreavey families
John McAreavey's uncle, Bishop John McAreavey, who married them on December 30, acknowledged that the younger generation would struggle to comprehend how the murder of one so seemingly pure could be part of God's plan. "One of the hardest things in life is finding that there are things that we cannot understand, no matter how hard we try," he conceded.
For some it proved just too much and medics had to attend to a number who fainted in the church grounds.
The service was painful and heart-rending, it could never have been otherwise at an altar that only days before still carried Mrs McAreavey's wilted wedding flowers.
But there were moments that gave cause to reflect on happier memories. One was when the tee-totaller's favourite indulgence - tea and biscuits - was presented as a symbol of her life.
But time and again the same theme recurred - her and John's devotion to each other.
"They lived for one another, they enjoyed and supported one another in everything," said Bishop McAreavey.
"Their lives revolved around one another, each talked endlessly about the other. Their hopes for the future were bound up with each other."
Those hopes were extinguished forever in Mauritius a week ago.
As the distraught groom emerged from the church as his beloved was carried on to the adjoining cemetery, one of the first to embrace him was President Mary McAleese.
Proof that his wife's death has not just broken his heart, but that of a whole country.