There is absolutely no doubt that Chase Carey, long-time Murdoch loyalist, is the most powerful executive in 21st Century Fox – whose surname does not begin with an M.

Three years ago, the man noted for both his unassuming nature and his flamboyant handlebar moustache, became the latest in a select line of News Corp executives to receive the ultimate public accolade, the official “bus” title: the person who would take over if Rupert Murdoch fell under a bus.

“Chase is my partner and if anything happened to me, I’m sure he’ll get it [the top job] immediately if I went under a bus,” said Murdoch at the time.

That was then. News Corp has not only survived the UK phone-hacking scandal, but is actually flourishing following the split of the company into separate corporate entities for the entertainment and publishing businesses – 21st Century Fox and News Corp.

Earlier, Carey had pushed Murdoch to go for a $5bn share buy-back to show confidence in the company and underpin its share price.

As well as being influential in the corporate split, the television executive – who does not share Murdoch’s love of newspapers – has also been credited by influential US trade paper, Adweek, with advising Murdoch to close The News of the World to try to limit the phone-hacking damage.

Yet, despite such achievements and Carey’s undoubted popularity with Wall Street, the dynastic dynamics have recently taken another twist in favour of family succession.

James Murdoch, former Chief Executive of News International in the UK, has weathered the hacking storm.

Meanwhile, his elder brother Lachlan has returned to the business from running his own company in Australia to take increased power. 

And in March Rupert Murdoch unexpectedly announced in an internal memo that Lachlan would in future be Co-Non-Executive Chairman of News Corp and its sister company, 21st Century Fox.

His brother James was elevated to become Co-Chief Operating officer of 21st Century Fox alongside Carey.

In a subtle touch, James Murdoch – despite his equal titular status – would still have to report to Carey.

It was probably a realistic nod to the fact that, while Chase Carey is very loyal to Rupert Murdoch, this could be stretched to breaking point if he had to report directly to the younger Murdochs.

If Carey has been put out by being leap-frogged again by a family member in the succession battle, there is no external sign of it.

He has continued doing what he does best, running the television and film business on a day-to-day basis and being one of the few whom Rupert Murdoch will listen to and even heed – a quality valued by investors.

He is widely seen as the operational counterpoint to Rupert Murdoch and a valuable brake on his corporate restlessness.

But who is Chase Carey?

While being personally understated, Carey is robust in fighting the public battles of the media owners.

The Financial Times noted recently that even his colleagues were not sure what lay behind the moustache.

“The greying thicket, delicately twirled at the ends may conceal a rugby wound or a car crash scar. Or it could be a diversionary tactic; one unavoidably noticeable feature of a man who otherwise presents a studiously low-­key face to the world,” the paper said.

In fact, the extravagant moustache is linked to a car crash suffered on the way to play rugby for his college team, but Carey’s low-key approach is equally real.

“He is very unassuming. If you ask him what his favourite lunch is, he would say cheeseburger and French fries,” says Marty Pompadur, a long-time Murdoch confidant, who now works for Macquarie, the Australian banking, financial services and investment group.

“But he is a very strong executive – a no-bullshit kind of guy. I have seen bankers present to him and he thinks for a minute and then says ‘No’ or, just occasionally, ‘Yes,’” adds Pompadur.

Carey is also a loyalist both to places and people, and he has a tendency to return to first base.

After a Harvard MBA he worked for Paramount Pictures before becoming a Murdoch executive in 1988. He ran Murdoch’s US satellite venture, DirectTV, from 2003 and stayed on when John Malone took over, adding 1 million new subscribers before returning to Murdoch in 2009.

Carey, naturally, had to spend time in Los Angeles as a television and film executive, but in 2000 returned with his wife Wendy and two children to live in the town where he was brought up, New Canaan, Connecticut.

And even though he earned more than $27m last year and is said to have the highest car allowance in the company, Carey is often seen on the commuter train from Manhattan to New Canaan with a can of beer in his hand at the end of the working day. 

Last year, in a rare case of Carey breaking cover outside Wall Street briefings, he talked openly to around 100 local citizens in the New Canaan Library about “Managing businesses in an increasingly volatile and complex world”.

He voiced support for Fox News and insisted: “I actually think its news coverage is fair and balanced.”

Asked about Murdoch’s corporate heir, Carey told his hometown audience: “I think Rupert’s going to outlast all his kids... He works seven days a week... but Rupert is quite clear: the decision on his successor will be the board’s choice, should that day come.”

While being personally understated, Carey is robust in fighting the public battles of the media owners.

Cable customers who think they can buy à la carte, subscribing on a channel-by-channel basis, “need a reality check”.

In June Carey and fellow broadcasters won an important legal battle against Aereo, the company providing simple aerials to access free-to-air television that allowed viewers to avoid cable subscriptions. The US Supreme Court ruled that Aereo breached broadcasters’ copyright.

Murdoch executives are united in their view of Carey’s redoubtable skills.

“I’m grateful that this formidable negotiator has always been my side of any argument or deal, rather than facing me,” says Mike Darcey, now Chief Executive of News UK, publisher of The Times.

“He is an exceptional executive, not only for his showbiz name and standout moustache, but for the formidable armoury he brings to the table,” says Darcey. “His calm and measured style is coupled with a fierce intellect, clarity of purpose and vast experience.”

Les Hinton, former Chief Executive of Dow Jones, publisher of The Wall Street Journal, clearly agrees. He emphasises Carey’s relaxed, almost genial, manner, lacking in pretence and happiest talking about Yankees baseball with a bottle of beer in his hand.

“But it’s a mistake ever to underestimate him,” warns Hinton. “As a boss he’s notorious for his terrifying command of detail. 

“He would fix with a fierce gaze any faltering executive; unblinking in negotiation; always ready to confront Rupert when he thinks he is about to make a mistake.” 

But despite the current odds, could the 60-year-old Carey actually inherit the top job one day at the insistence of the board or of 21st Century Fox shareholders?

It has to be said that it would not make much difference if he did. The way the company is structured means, irrespective of who holds the top title, it will remain a family business controlled by the Murdochs, who are supported by the second-largest voting shareholder, the Saudi multi-billionaire, Al-Waleed bin Talal.

And one thing you can be absolutely sure of: Chase Carey is more than smart enough to be very aware of that reality.

Chase Carey, President and COO of 21st Century Fox, is a keynote speaker at the RTS London Conference, ‘Power, Politics and the Media’ on 9 September.