The former diplomat's maiden speech to the House of Representatives in July 2019 carried the warning that historic pillars of the nation's security were under strain. Mr Sharma put it bluntly: Australia's strategic holiday was over.

His speech identified the reasons: the United States' desire to take global leadership had waned, its relative power was eroding, and the rules-based international order was being tested.

As geopolitical shifts and COVID-19 have brought foreign affairs to the front of Australia's agenda, Mr Sharma's former career has given him a clear voice from the backbench.

Before Mr Sharma, 44, successfully ran for the NSW seat of Wentworth in the 2019 federal election, he spent almost two decades in the public service and was rising fast in the ranks of the Department of Foreign Affairs and Trade.

Since entering parliament, the Liberal MP has been a source of foreign policy thinking that has expanded the debate about Australia's role in the emerging new world order.

"A lot of people view this as a bit of a specialist debate or an insider's debate or a beltway debate, but we do need to have all politicians, and that's all sides of politics, but also from all parts of the country, all electorates, all backgrounds, involved in some of these discussions and decision making, because it's Australia's future we're talking about and Australia's neighbourhood we're talking about," he says.

Mr Sharma reflected on the public service in his maiden speech to parliament. At its best, he said, the bureaucracy was a creative and rich source of ideas, blunt in its advice but unswervingly loyal to the government of the day.

His public service career started at DFAT in 1999, soon after he finished a master's degree at the University of Cambridge, where he also earned first class honours in his undergraduate studies. Early in his diplomatic career, he was stationed in Papua New Guinea for more than three years, helping negotiate an end to the civil war in Bougainville.

A fast ascent within the diplomatic service followed. Before his appointment as ambassador to Israel at age 37, he was a political counselor from 2006 to 2009 at the Australian Embassy in Washington, D.C. Between 2010 and 2012 he led the international division in the Department of the Prime Minister and Cabinet in Canberra, where he helped spearhead prime minister Julia Gillard's diplomatic efforts.

He would have risen further in the public service, but for his move into the private sector in 2017, and later, politics, says former PM&C secretary Terry Moran.

Mr Moran remembers Mr Sharma as an acute, perceptive and strategic PM&C executive able to construct strong advice.

"He had the instincts of a formidable policy adviser," Mr Moran said.

"Invariably the advice was intelligent and likely to lead to a good result.

"In PM&C I trusted his professional judgment as it had been tested many times and found to be first rate."

Mr Sharma says he embraces the idea that the public service's advice should be "frank and fearless", but adds it should be tailored to the government's priorities and political context of the day.

He's forthright in his views on how Australia's diplomatic service should operate in a more dangerous world. Mr Sharma made headlines this month arguing in an opinion article that DFAT would need to re-embrace the task of influencing the nation's strategic environment as its primary mission.

The department had failed in the Canberra bureaucratic struggle for resources, and Australia's remained one of the smallest diplomatic services within the G20, Mr Sharma wrote.

Asked about his comments, he says DFAT's budget has remained the same in 20 years despite the national security and international challenges of those decades.

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Meanwhile, Australia has increased its defence spending, grown its national security apparatus, created the Department of Home Affairs, and boosted funding for intelligence agencies.

"You've got a situation where there's a whole lot more players in this national security, foreign space that are a whole lot better resourced than DFAT and have a whole lot more personnel and control of budgets, and DFAT's still has the same size, same budget, but with more competition, it has a diminished role."

The causes cannot be pinpointed to a single government, minister or secretary, he says.

"It's a bit more broad ranging and structural than that.

"Some of this is attitudinal. There is still a kind of an assumption within Foreign Affairs that they are an indispensable part of government, and that's true to a point, but that's been cut back to their indispensable role, whereas other departments and agencies are always, they don't take their positional relevance for granted so much, and they're prepared to fight a bit more.

"DFAT needs to fight more for its place at the table, it won't always be given it as a matter of right."

As a public servant he saw other agencies come to the government with solutions to challenges, and make the case for additional funding.

"DFAT just hasn't done that. So it's not like anyone has set out to punish them, they just haven't had their hand out when the government's said 'we've got more resources'," he says.

"We really need Foreign Affairs to put up its hand and say 'we can do this for you, we've got a plan and we're going to do it this way, we're going to do it that way, we need more resources, but this is our vision, this is how we can give you a solution to this problem'.

"And I think that proactive, future-oriented posturing is what's really been lacking from DFAT over the past 20 years."

George W. Bush was halfway through his second presidential term when Mr Sharma joined the Australian embassy in Washington.

The young diplomat worked with then-Australian ambassador to the US Dennis Richardson, who describes him as thoughtful, "quite tough-minded", and respected both individually and for his intellectual depth.

By the time Mr Sharma returned to Australia in 2009, Barack Obama had been elected and was overseeing a foreign policy that took a more modest and restricted view of the US' role in the world. Mr Sharma witnessed the shift during his stint in the US, where there was a war weariness by 2006, a few years into the Iraq War.

He says the Trump presidency continued the trend of US reluctance to underwrite the global order, a national attitude that would not change with the November election result. As the strategic environment transformed, Australia would need to make a more active, "full court" diplomatic effort that viewed European nations as strategic as well as economic partners, and that thickened relations with nations in the US alliance network including Japan and Korea.

Australia had relied on the "hub and spokes" structure of the US alliance network.

"Increasingly the hub is less strong and less engaged and so the spokes need to kind of build their own links together and find ways to work together."

It's speculated Mr Sharma's rise in politics could rival the speed of his ascent in the bureaucracy. Commentary labelling him "cabinet material" began during his first, unsuccessful tilt for Malcolm Turnbull's former seat in 2018. He was touted for possible promotion in one media comment piece this month on the Coalition's ministerial reshuffle options ahead of Liberal senator Mathias Cormann's looming departure.

Mr Richardson echoes Terry Moran's views about what Mr Sharma might have achieved had he stayed in the bureaucracy.

"I have no doubt if he had remained in the public service, he would've become a department head," Mr Richardson says.

Mr Sharma doesn't let differences in views become matters of personal animosity, he says.

"He doesn't lose friends because of the way he carries an argument, and that I think you saw both in the Wentworth byelection and the general election, when he retained a respectful relationship with his political opponents."