Sally McManus started her job as the country’s most powerful trade union leader amid howls of criticism.

Shouted down for suggesting union members were right to break “unjust” industrial laws in a live TV interview, McManus quickly adjusted to the high decibel work of being secretary of the Australian Council of Trade Unions.

Now, nearly a decade later, she is ready to turn the volume down.

“I’m looking forward to having a break,” McManus told Guardian Australia ahead of handing over the job at the end of the month.

“It’s been 33 years as a union official, 22 of them as a leader, and nine and a half as ACTU secretary. It never stops.”

McManus announced her departure last month, on the same day ACTU president, Michele O’Neil, revealed plans to step down as well. Anthony Albanese described both – the first all-female leadership team in the ACTU’s 99-year history – as “giants of the labour movement”.

McManus has helped reshape Australia’s industrial landscape, pushing the Albanese government and business on a worker-friendly agenda.

Along with O’Neil, she has helped lead campaigns for same job, same pay protections, laws giving workers the right to disconnect, wage theft criminalisation and ensuring minimum pay, insurance and safety standards for gig economy workers.

Her tenure has spanned the Turnbull, Morrison and Albanese governments, economic disruption from the Covid-19 pandemic, Labor’s jobs and skills summit, allegations of corruption and lawlessness by union leaders, including the CFMEU, and, a year ago this week, the productivity roundtable convened by the treasurer, Jim Chalmers.

McManus says some of her closest held victories include wage rises for low-paid workers, help for women and children affected by domestic violence and helping strengthen key industries including early childhood education and aged care.

But the high profile role has brought pressures.

Since that first ABC TV interview on the day she was elected in March 2017, McManus has faced the “inner most horribleness” of critics – online and in real life.

She has received death threats and tirades, a darker side of the job McManus says she tries to ignore.

“I would say it has become 10 times, maybe 20 times, worse, and that’s got a lot to do with what happened with X and also just the continued monetisation of social media.

“Back 10 years ago … you could actually have communities of like-minded people on social media, and not have to experience all the horribleness.”

The job isn’t done, McManus says.

She points to the rapidly shifting reality of work, including AI threatening the rights of employees. Having long advocated for tax reform in Australia, McManus wants more work on intergenerational equity and help for vulnerable people.

She nominates Pauline Hanson’s growing political support as a priority for the labour movement, warning the One Nation leader would end unfair dismissal laws if the party ever secured power.

McManus considers a four-day work week realistic in the future.

“If, in the end, AI becomes a wonderful thing and we don’t have to work as much because it’s replacing jobs, well, people still need to live and to participate in society.

“The way to do that is to cut working hours with no loss of pay … and that’s something that we could actually do in Australia.”

Asked about allegations of criminal behaviour and corruption within the CFMEU, McManus says a series of leaders in the controversial construction union had betrayed members.

“Somewhere along the line, it’s hard to actually know when, the previous leaders of the CFMEU in at least three of the states completely walked away from union values and what was acceptable, for not just the majority, but 95% of unions,” she said.

“That whole experience just caused the rest of the union movement to really sharpen what that line is that we say cannot be crossed, and that’s corruption and that’s violence.”

Victoria is preparing to initiate a royal commission into corruption on the government’s Big Build infrastructure program, expected to include evidence about CFMEU activities.

McManus is blunt about the personalities involved.

“I don’t consider them unionists. I don’t consider them to have union values. It’s easy for people to be performative unionists, to wear the gear and to sometimes talk the talk. [It’s] that much harder to walk the walk.”

The 55-year-old says she is not at all tempted to enter politics. Instead, McManus plans to go bird watching and undergo surgery for a cochlear implant to fix hearing loss.

“I’m not undertaking that lightly. It takes some significant attention in terms of rehab, and I want to give myself the best chance of getting as much of my hearing back as I can.”

Incoming ACTU secretary, Melissa Donnelly, now the national secretary of the Community and Public Sector Union, will succeed McManus on 31 August.