Yet the night before the results of Australia's historic vote on legalising same-sex marriage became public, Jacob White couldn't sleep. He wasn't taking anything for granted.

"At no point were we 100 per cent confident that there would be a yes result," Mr White said.

"Right up until they announced the result, I was about 50-50. I was unsure of how it would go and terrified that the country might say no."

Mr White was the director of the ACT Yes campaign. He said there were more subtle changes in society as result of the survey, in addition to allowing same-sex couples the right to wed.

"There are more same-sex couples holding hands as they're walking down the street. There are more people in the community that are comfortable talking about these things now," he said.

The final result on November 15, 2017 showed 61.6 per cent of more than 12 million voters said yes. A month later in a resounding display on the floors of parliament the vote was legislated.

After failed attempts at free votes in parliament to change the marriage laws, the idea of a non-compulsory, non-binding postal survey conducted by the Australian Bureau of Statistics was brought about by a staffer of then-Attorney General George Brandis in July 2017.

Following an unsuccessful High Court challenge, campaigning quickly began but was stretched out over two months.

It was a challenge Mr White recognised from the start, and he helped set up an army of volunteers.

"We had around 800 people involved in the ACT campaign, and that included people making phone calls and door knocking and attending stalls and handing out flyers," he said.

While there was a coordinated approach across Australia through social media and advertising, the campaign strategy in Canberra was unique.

"It was more straightforward to doorknock," Mr White said.

"There's a much smaller proportion of high-density apartments, so we could reach front doors a lot easier."

That led to the largest doorknocking exercise in the country, reaching 30,000 houses over four days.

Despite enthusiastic support for the "yes" vote, there were times when the campaign became personal for supporters.

Mr White said the two-month campaign was deeply damaging to thousands in the LGBT community.

"It was a rough campaign, and lots of people took that pain onboard, and there was suffering and needless pain," he said.

"Every night for two months, we made phone call after phone call, and every night we would have a debrief and talk about the things people said to us on the phone," Mr White said.

"Often the volunteers would burst into tears because of some of the offensive things said to us. There were good stories about people saying they were voting yes, but there was rarely a night where something negative wasn't said."

Andrew Barr said he's wary of getting too complacent about the results during political campaigns, a lesson he learned the hard way during the unsuccessful 1999 referendum for Australia to become a republic.

The ACT Chief Minister told the Sunday Canberra Times he took that experience into the postal survey.

As the first openly gay leader of a state or territory and a member of parliament who voted to legalise same-sex marriage in the ACT during 2013, Mr Barr said he felt an extra weight of responsibility.

"Premiers and Chief Ministers can elevate issues and can get more attention on a particular debate, but that support alone doesn't deliver a result," he said.

After campaigning for same-sex marriage for the better part of a decade, Mr Barr said change was inevitable, although he never expected the postal survey to turn out the way it did.

"I'm an opinion poll and data nerd, so I was looking over the polls and I knew pretty well what the result was going to be.

"The only thing that was a surprise was the strength of the result in the ACT, being so far ahead of the the national result.

"I expected it to be an order of magnitude above [the national result], but the vote was even stronger than I had expected it."

Mr Barr was initially against the idea of a postal survey, telling a rally shortly before the Hight Court challenge was struck down that the method would be opposed.

However, when the survey came to pass he said he would campaign strongly, aiming for the ACT to have the highest "yes" vote in the country.

Mr Barr even made the unusual step to volunteer to vote on behalf of others if they couldn't make it to the post box, and although six Canberrans got in touch about the offer none followed through.

While the yes vote was backed throughout Canberra with the help of rainbow buses and flags, Mr Barr attracted controversy with his decision to use taxpayer money to support the campaign, a decision he defends.

"It was a decision of the ACT parliament, and I sought parliamentary approval for that course of action, so it was appropriate in this instance.

"I would anticipate any chief minister would seek similar parliamentary approval for this sort of action in other hypothetical circumstances."

When asked if much has changed in the year since the survey, Mr Barr laughed, saying enough happened in the time since to make it feel like two.

He said the survey increased the happiness levels in the ACT, including his own.

"It certainly proved that it was possible for same-sex marriages to occur and the sun would come up the next day and life would go on for everyone," Mr Barr said.

"The only difference was that there were a group of Australians that were treated equally to fellow citizens and there was a net increase in happiness because these couples were able to get married in front of family and friends."

For a little more than four minutes, David Kalisch had the nation hanging off his every word. But the chief statistician for the Australian Bureau of Statistics said he didn't want to drag it out.

"It was quite clear that for the result to be accepted people needed to trust them, and I wanted to go through the metrics of it all," he said.

Mr Kalisch said the postal survey was a chance for the bureau to rebuild public trust following the controversy of the 2016 census, when the census website was unavailable for several days due to technical issues. But while they have five years to prepare for a census, they had just months to carry out the survey.

"It was a pretty daunting prospect, and as soon as we heard that we were going to do the job, we had to think carefully about whether it was possible," he said.

Mr Kalisch found out about the survey as he was returning from a trip away. He received a phone call from then-treasurer Scott Morrison.

A day later the decision was made public, and the race against the clock began.

At its peak, 500 bureau staff were working around the clock, many moved off existing projects such as the 2021 census. Space in their refurbished building was set aside purely for the postal survey taskforce.

More than 12 million survey forms were posted, about 80 per cent of eligible voters. While vote counting was done electronically, all 12 million envelopes had to be opened by hand. Semi-trailers full of completed surveys were arriving on an almost daily basis.

Along with the scale of implementing the survey, Mr Kalisch said there were other challenges, like reaching voters in remote communities and those overseas.

"The challenge was not only to deliver the survey, but to deliver a high-quality survey that had both public acceptability and support across the parliament and the community would have to recognise the results had integrity," he said.

Despite the many hurdles, Mr Kalisch said everyone rose to the occasion.

"One of the most important things was early preparation. Everything was happening at breakneck speed and people had to respond to a tight timeframe," he said. "People across the board stepped up and delivered."

Before the results were announced, Jacob White was preparing for either outcome. While he was hoping for a resounding "yes", speeches were ready to go in the event of a "no".

"What people didn't see was a pastoral care element and support services being on hand if it turned out we had a 'no' result," Mr White said.

Thankfully, he said, that didn't come to pass. For many Canberrans, the lasting memory of the result was a street party that took over Lonsdale Street.

Not only was there the result to celebrate but the ACT had the highest proportion of "yes" voters in the country, with 74 per cent of the territory in support of same-sex marriage.

Party planning began four days out, in order to shut down the Braddon street.

"All the people knew it was a special occasion, and people got around the street closure," Mr White said.

"There was a huge celebration of the positive outcome, and not just the LGBT community, but the whole of the Canberra community joined us on the street that day."

While a street party was always planned in the event of a positive result, the scope was expanded after the result was announced, Mr Barr said.

"The scale of it increased tenfold with the result itself," Mr Barr said.

"All of a sudden we were joined by a cast of thousands and people from federal parliament. Many were surprised that Canberra could throw such a good party."

Mr White said despite the challenges, he will always remember the outpouring of joy after the vote.

"The process was unnecessary and highly damaging. We hope that we don't see that process used to decide the rights of any other Australians at a point in the future," he said.

"But in the end, on November 15, it was like a big, warm hug from the Australian community to the queer community."