By 14, Barr was following politics closely, by 18 he had joined the Labor Party, and at 33, after working as a political staffer for most of the intervening years, he was a member of that parliament. In short, he is a creature of politics.

While his family was clearly immersed in a political world, his parents didn't join the Labor Party until recently, and Barr describes his Canberra relatives the "southern outpost of quite a conservative tradition".

The other branch of his family headed north to Brisbane, where his uncle, Major General Peter Arnison was a National Party appointee as governor of Queensland. It's not an unfriendly divide, with his National-voting aunt donating $50 to his campaign for re-election on Saturday.

Barr is close to his family, with regular Sunday meals at his brother's house in Campbell with his brother's two young children to whom Barr and partner of 17 years Anthony Toms are dedicated uncles. Barr doesn't think he and Anthony will have children of their own and he sounds resigned rather than happy about that reality. "That's life, some things work out, some things don't," he says.

His parents were just 17 and 18 when he was born, his mother still in year 12. His only brother is six years younger. When he made his first speech in 2006, he was 33, and he pointed to the average age in his electorate - just 34.

Much is now being made by Barr's political opponents about his focus on the under-40s to the detriment of older Canberrans, and while much of this attack is considerably overstated, he himself fuels the idea.

He has hit back at activist community groups, who are largely older, as unrepresentative. And in that first speech he spoke of the "brutality" of the baby boomers foisting expensive educations on to generation X and pricing them out of owning a home.

It is intriguing that when asked about Jon Stanhope's regular and politically unhelpful interventions on issues such as affordable housing, poker machines and party factions, Barr points, among other things, to Stanhope's age. The men share a birthday, Barr says, but Stanhope is older than his father. There is a generational divide.

Barr spoke in his inaugural speech in 2006 of gay law reform inspiring his entry to politics. As the first openly gay leader of an Australian government, he has spoken more than once of his struggles at school as a teenager who did not fit the heterosexual norms.

And asked in our interview last week about a reticence or defensiveness in his character, he responded, "I keep certain things intensely private, for obvious reasons, given what happens when certain things become public. I don't want to labour on this point but some of the homophobic stuff that is said out there is reasonably confronting."

But his political focus and passion is really elsewhere. A member of Labor's right, for Barr the economy comes first.

If his politics has an edge of distrust, it also has an edge of reformism - not the ambitious and intellectual agenda of Simon Corbell, nor the fired-up human-rights and justice agenda of Jon Stanhope, but an agenda that champions internationalism and vibrancy, that envisages Canberra as Australia's version of New Zealand's "cool little capital".

He has led Labor's tax-reform program since 2012 to significantly increase rates and land tax as replacement revenue for phasing out the stamp duty tax on property sales. While widely lauded as sound policy, this is a plan of enormous political difficulty.

The ACT budget is not in pretty shape, with spending way surpassing revenue year on year. But while Barr entered parliament citing a surplus as important for the ACT's credit rating and for intergenerational equity, as Treasurer he talks about the economy, rather than the budget. The budget is a tool to drive economic outcomes, he says, and he has zero interest in a surplus for its own sake.

"I'm interested in the ACT's economic performance, not some accountant's view of where the budget should be. So I take an economist's view that if our economy, as it is, is transitioning back to a period of trend growth then I want the budget in surplus in that context."

It was a budget austerity measure that brought Barr what he says was his most difficult time in government, when, six weeks into his political career and four weeks as education minister, he was tasked with closing a slew of schools.

"Jon Stanhope says here's this report and off you go and implement it," Barr recalls, counting nothing as challenging since.

You might think Barr would judge this Saturday's election - his first as chief minister - as one his most confronting political challenges. But he dismisses the suggestion, insisting the 2008 election was worse, when Stanhope was "really on the nose" over school closures, and one in four supporters deserted Labor, whose primary vote fell from 50 to 37 per cent.

Barr characterises this weekend's election as not dissimilar to 2012, but with the advantage that in 2012 the "Gillard Rudd fiasco" was playing out federally whereas now the federal dysfunction is on the conservative side.

Barr points to the July Senate result (Labor 38 per cent, Liberals 33 per cent, Greens 16 per cent) as an indicator of how he expects people to vote on Saturday.

All of which would appear to suggest he counts himself in a good position to retain government.

Barr has Labor polling, along with focus groups and what he says is the most extensive field campaign in ACT Labor's history to inform his view, and he refers again to the attitudes of the majority who aren't among the activist minority whose views are heard. Perhaps he is right.

If Barr is returned he will have to traverse some boggy factional terrain given internal disquiet in the left, the traditional powerhouse of the ACT branch, with the degree of difficult will be determined partly by the left-right numbers in caucus. He has failed so far to endorse the Left's Yvette Berry as his deputy, although endorse her he surely must. This is perplexing and even provocative, while perhaps not out of character.

Despite the difficulties, Barr's take on the campaign is positive.

"What's been pleasing for me over the last five weeks has been just how strong the positive feedback has been. And people are urging me to continue on through what's been a fairly concerted negative campaign by a range of political opponents," he says. "Look, in any election you are never as popular as your enemies would hope, nor as popular as your closest friend would want you to be."