It is an alliance that has been forged, and perhaps even consummated, in Ireland. This certainly was the geographical location for the former Manchester United and Celtic player as he went about his duties as the assistant manager of the Republic yesterday.
These did not include speaking to the media. Keane was due to appear at a press conference last night but his place was taken by Martin O'Neill, the manager of the Republic of Ireland, who was typically canny in dealing with inquires about the future employment of his assistant.
He confirmed what was obvious from the moment Keane's name was linked to the Celtic job - that the approach had been made by Dermot Desmond, the major single shareholder at Celtic, an Irishman of considerable wealth and clout.
The moment when O'Neill and Desmond conversed had a poignancy probably ignored by both those redoubtable figures. O'Neill was Desmond's choice for the Parkhead job and once they must have talked about the signings, the hopes and the ambitions.
Now Keane, a bristling but charismatic figure particularly in his homeland, has found favour with the businessman who is a powerful, influential force at the club. Sources at Celtic last night insisted no-one had yet been offered the job and that an appointment was not imminent. The Irishman is one of several people under consideration. However, the media frenzy around Keane increased as Irish sources, close to the Football Association of Ireland, insisted talks had started between club and coach.
It is almost redundant to state that the appointment of Keane would be a gamble. His track record as a manager is as patchy as a potholed Glesca road and the excesses of personality can have the devastating effect of setting off a grenade inside a telephone box.
He may be a changed man and he may have learned much from his experiences as a manager of both Sunderland and Ipswich Town. But no-one can be quite sure. He certainly has the drive and ambition to be a leading coach and he has a sharp intelligence that has not always served him well.
It is not difficult to see what Celtic offers Keane - a step back on the managerial ladder after two major stumbles, a chance of redemption. Celtic offer almost certain domestic success, gilded by a chance to manage in the group stages of the Champions League, although qualifiers must be negotiated. Keane, still fascinated by football and the challenges of being part of a winning team, will not receive a better offer, certainly short term.
But what does Keane offer Celtic? First, there is no obvious candidate for the Parkhead job and most contenders have blemishes on their CVs. Even Henrik Larsson, the beloved player of the glory days, is unproven as a manager. This is not an outstanding field of runners, particularly if Celtic stick to the traditional managerial role rather than bringing in a coach under a director of football.
Keane's allure is that he is a "big name" with possibilities. He is regularly accompanied by the smell of cordite but still holds a whiff of glamour; one of the great players of Manchester United, a captain who would drag his team-mates over the winning line as if they were a pack of unruly pups. He has undoubted leadership qualities though he has the ability, too, to alienate.
The thinking may be that Keane can finally use his knowledge, wit and charisma to galvanise a Celtic team that faces realistic challenges almost exclusively in European terms. There may even be the temptation to believe Keane would raise the profile of the club or help shift season tickets - assumptions rather than sober forecasts.
Any hiring of Keane would have to include a safety valve. The Irishman walks alone, like the gunslinger in a hackneyed western. But he will need someone by his side for life in the SPFL Premiership, particularly with a media that demands a Celtic story every day.
Keane, frankly, would require a presence that not only appreciated the realities of working in Scottish football but also represented a buffer for a character who finds confrontation with remarkable ease.
It would be more than fascinating, too, to watch Keane, accustomed to driving in football's fast lane, become attuned to the prudent economic strategy at Parkhead. The Celtic model of recruitment and selling has proved financially successful but it can also be frustrating for those who have to work within it. It has to be accepted, however, and this will test Keane.
The first robust exchange of views between Peter Lawwell, the chief executive, and Keane over a transfer target would surely clear the debt of Greece if put on pay-per-view. It would make Froch-Groves seem like a spat over a rubber toy in a crèche.
The "Keane to Celtic" tale is as yet an unfinished story but it requires careful reading on both sides of the deal. Keane, bold and confident, may believe he has nothing to lose but he would also be moving into an environment that is both strange and capable of making demands that he cannot fully understand.
Celtic may just be investigating an intriguing possibility but it is one that carries jeopardy as well as opportunity. The precise calibration of these opposites has made Desmond very rich. However, the wealthy often get what they want but sometimes not what they need.