'Lucky' Bill Shorten offers one more zinger, as he prepares to leave ...

Bill Shorten had one last "zinger" to offer when announcing his retirement from politics, as a journalist asked for an inside look into the conversations that led to his decision.

"I think you would be one of the great fly fishermen of Australia, with that bait you're dangling," Mr Shorten joked as he spoke in the prime minister's courtyard.

The former Labor leader never stood in that courtyard as prime minister, but he has loomed large in the party since his election as MP in 2007.

Mr Shorten entered parliament after rising to national prominence in the wake of the Beaconsfield Mine disaster.

As secretary of the Australian Workers Union, he became the de facto voice of families and communities while two mine workers were trapped underground for weeks.

Bill Shorten addressing the media at the Beaconsfield mine in 2006. (AAP: Dale Cumming)

He was elected to the federal parliament the following year, winning the safe Labor seat of Maribyrnong in outer Melbourne — a seat he had unsuccessfully vied for a decade earlier as a 28-year-old.

A rapid rise

Mr Shorten, as a factional heavyweight in the Victorian right, quickly rose through the ranks of the Labor Party.

He was given an immediate spot in former prime minister Kevin Rudd's outer ministry as the junior minister for disabilities — a role that would come to define much of his career in parliament.

Beyond policy, Mr Shorten quickly revealed himself to be a political creature, playing a key role in the removal of Mr Rudd as leader when his leadership was challenged by Julia Gillard in 2010.

Under Ms Gillard, Mr Shorten was elevated to cabinet as minister for financial services and minister for workplace relations.

Bill Shorten entered cabinet under Julia Gillard. (AAP Photo: Alan Porritt)

An awkward 2012 interview with David Speers became embedded in the political firmament when Mr Shorten defended comments on a rolling scandal involving the house speaker by Julia Gillard — which he had not heard.

Shorten: "I understand the prime minister has addressed this in a press conference in Turkey in the last few hours. I haven't seen what she said, but let me say I support what it is that she's said."

Speers: "Hang on, you haven't seen what she said —"

Shorten: "But I support what my prime minister's said."

Speers: "Well, what's your view?"

Shorten: "My view is what the prime minister's view is."

His activities as a factional player often gained more attention, and he was instrumental in the ousting of a second prime minister — Ms Gillard — when she was challenged by Kevin Rudd in 2013.

He finally took on the leadership himself after Labor's disastrous result at the 2013 election — Mr Shorten said he became leader at the party's lowest ebb since 1996.

On the losing end of the 'miracle' election

Over the next two terms, Mr Shorten led the party's return after several years of factional infighting.

Labor performed extremely well at the 2016 election, picking up 14 seats in a campaign that capitalised on concerns the Coalition would privatise Medicare if they won.

The then-leader was known for "zingers" — one-liner sledges that missed as often as they landed — and a few daggy dad moments, like an attempt at small talk with a grocery shopper on their favourite type of lettuce.

Bill Shorten let his hair down while visiting the island republic of Kiribati in 2015. (ABC News)

At the 2019 election, Labor was the frontrunner to win after the Coalition had endured its own period of leadership turmoil.

But under Scott Morrison, the Coalition defied expectations, pulling off a "miracle win" and ending Mr Shorten's career as Labor leader.

The Labor Party concluded the public was not ready for an overly ambitious agenda, which included a renewed push for a republic, a substantial lift in Australia's climate targets and major tax reform including changes to negative gearing and franking credits.

Mr Shorten also wore blame as an "unpopular" leader and he was replaced by his rival, Anthony Albanese.

Bill Shorten stepped down as Labor leader after losing the 2019 federal election. (ABC News: Matt Roberts)

Mr Shorten grieved his "disappointing" election loss but quickly took the horns of the developing Robodebt scandal.

He spearheaded the Robodebt campaign, which ultimately led to findings of its illegality and a royal commission into the debt-raising program.

Prime Minister Anthony Albanese said on Thursday morning that Mr Shorten "channelled the disappointment of 2019 into fighting for justice for the victims of Robodebt".

Shorten seals a final deal with the NDIS

After the election of the Albanese government and Labor's return to power, Mr Shorten was appointed minister for the NDIS and government services, returning to the portfolio he was first given 15 years earlier.

Mr Shorten had been instrumental in the introduction of the National Disability Insurance Scheme, "widening Australia's social safety net" to include a national program to support Australians with permanent and significant disability.

Bill Shorten has served as NDIS minister under Anthony Albanese. (ABC News: Nick Haggarty)

In the decade that followed, successive governments sounded warnings that the NDIS was rapidly growing in cost, and after the 2022 election, the newly elected Albanese government agreed the scheme would become unsustainably expensive without change.

Mr Shorten was charged with significant reforms to rein in its growing cost, which were passed with the support of the Coalition just three weeks ago.

In his maiden speech to parliament, Mr Shorten set out the challenge for him "not to fit people with disabilities around programs but for programs to fit the lives, needs and ambitions of people with disabilities".

"The challenge for all of us is to abolish once and for all the second-class status that too often accompanies Australians living with disabilities," Mr Shorten said in his speech.

Having ensured the scheme he helped to create would survive, Mr Shorten stepped out on Thursday to call time on his political career.

'In the end, we are all just passing through'

Mr Shorten said now in his 50s, he had begun to reflect on the highest and lowest moments of his time in politics, and what might come next.

Just two years ago his close friend, ally, and Labor Party colleague Kimberly Kitching died suddenly.

Speaking to the ABC at the time, Mr Shorten wept as he said he talked about the toll politics may have taken on his friend.

"You can never dial forward and predict back what's going to happen," he said. "But you do wonder if she would've been better off never going near politics."

Looking over his career, Mr Shorten said there had been good days and terrible days, but that there was "not a single day" he would hand back.

Opposition Leader Peter Dutton said Mr Shorten had been a "decent" man, who recovered well from a disappointing election loss and "showed a level of dignity and respect to our democratic process that he should be honoured for".

Though he never achieved his ultimate aim to become prime minister, Mr Shorten said he felt he was one of the "luckiest people in politics".

Entering politics, Mr Shorten pledged to be a "consistent and persistent Labor parliamentarian".

The prime minister said Mr Shorten had maintained his relentless energy and "determination to see the job through".

Mr Albanese asked Mr Shorten to stay on a little longer, to finish the job with the NDIS, before taking on a new role as vice-chancellor at the University of Canberra.

"In the end, we are all just passing through, what matters is whether we leave the place better than we found it," Mr Shorten said from the prime minister's courtyard.

"Today is not my valedictory, there is plenty more work to be done."