Shorten was born on 12 May 1967 at St Vincent’s Hospital, Melbourne, the son of Ann Rosemary (née McGrath) and William Robert Shorten. He has a twin brother, Robert. According to a statement given during the 2017–18 dual citizenship scandal, Shorten held British citizenship by descent until 2006, when he renounced it in order to run for parliament.

Shorten grew up in Melbourne’s south-east, living in Murrumbeena or Hughesdale. He attended St Mary’s Catholic Primary School in Malvern East. He and his brother were offered scholarships to De La Salle College, but their mother instead chose to send them to Xavier College, Kew. They began attending Kostka Hall, the college’s junior campus, in 1977. Shorten was chosen for the state debating team in 1984, his final year at the school. He excelled at fencing and was the state under-15 champion in the sabre division.

In 1985, Shorten began studying at Monash University, graduating with a Bachelor of Arts in 1989 and a Bachelor of Laws in 1992. He was active in student politics, both in the university’s ALP Club and in Young Labor. He helped establish Network, a Labor Right-aligned faction of Young Labor; in 1986 it “took control of Young Labor from the Left for the first time”. Shorten briefly worked in a butcher’s shop during his first years at university, and was also a member of the Australian Army Reserve from 1985 to 1986, holding the rank of private. He volunteered in Senator Gareth Evans’ office, and then after the 1988 Victorian state election was employed as a youth affairs adviser to Neil Pope, a Victorian government minister. He took a gap year in 1990, travelling overseas for the first time and backpacking through Central Europe. He was subsequently involved in Network’s abortive attempt to take over the state branch of the Australian Theatrical and Amusement Employees’ Association.

Shorten’s mother was a university academic and lawyer who completed a doctorate at Monash University and ended her career there as a senior lecturer in education. She completed a law degree later in life and practised as a barrister for six years. She was originally from Ballarat, descended from “a long line of Irish Australians” who arrived during the Victorian gold rush. Shorten’s father was a marine engineer born in Tyneside, England. After settling in Australia he worked as a manager at the Duke and Orr Dry Docks on Melbourne’s Yarra River, where he was frequently in contact with union leaders. Shorten’s parents divorced in 1988 and his father remarried a few years later. He subsequently became estranged from his father, who died in 2000.

After graduating, Shorten worked for twenty months as a lawyer for Maurice Blackburn Cashman. In 1994, he began his union career as a trainee organiser under the ACTU’s Organising Works program at the Australian Workers’ Union (AWU), before being elected Victorian state secretary in 1998. His time as secretary was marked by a reform of the union’s structures.

Prior to the 1996 federal election, aged 28, Shorten contested Labor preselection for the Division of Maribyrnong. He was defeated by Bob Sercombe, who went on to retain the seat for Labor at the election. In February 1998, Shorten won preselection for the safe Labor seat of Melton at the 1999 state election. He was not a resident of the electorate, located on the rural–urban fringe to Melbourne’s north-west. He subsequently resigned as a candidate in order to become state secretary of the AWU.

In March 2000, Shorten married Debbie Beale, daughter of businessman and former Liberal MP Julian Beale. They divorced in 2008. In 2009, Shorten married Chloe Bryce, daughter of then Governor-General Quentin Bryce.

Shorten was elected as the AWU’s national secretary in 2001 and was re-elected in 2005. He resigned as Victorian state secretary of the AWU in August 2007. He was an active member of the Labor Party and was a member of the party’s national executive until 2011, as well as the administrative committee of the Victorian branch. He was also director of the Superannuation Trust of Australia (now Australian Super) and the Victorian Funds Management Corporation. From December 2005 until May 2008 he was the Victorian state president of the Labor Party. He was also a member of the Australian Council of Trade Unions executive. Until early 2006, he was a board member of GetUp.org.au.

During his time as AWU national secretary, Shorten was the interim chief executive of the Australian Netball Players Association (ANPA), following an alliance between the AWU and ANPA in 2005. Shorten also served on the advisory board of the Australian Cricketers’ Association.

In 2005, Shorten announced that he would again seek preselection for the Division of Maribyrnong, challenging Bob Sercombe (the sitting member and a member of the Beazley shadow ministry). Justifying his challenge to an incumbent Labor MP, Shorten said, “…we haven’t won a federal election since 1993. When your footy team loses four consecutive grand finals, you renew the team.”

At the 2007 federal election, Shorten was elected to the House of Representatives as the Labor MP for Maribyrnong. It was speculated that with his high public profile and general popularity within the Labor Party, he might immediately be given a front-bench portfolio; however, when asked about the possibility, new Prime Minister Kevin Rudd said that he believed parliamentary experience was essential when designating front-bench portfolios. On 29 November, Rudd announced that Shorten would become Parliamentary Secretary for Disabilities and Children’s Services. As Parliamentary Secretary, Shorten pushed hard for the National Disability Insurance Scheme, something which was later to become a key policy of the Labor Government.

Shorten would later become one of the main factional leaders involved in the replacement of Kevin Rudd as Prime Minister and Leader of the Labor Party with Julia Gillard in the 2010 leadership challenge.

Following the 2010 federal election, there was speculation that Shorten might seek to oust Prime Minister Julia Gillard from her position within the year; former Labor Prime Minister Bob Hawke and former Labor Opposition Leader Kim Beazley had both previously endorsed Shorten as a potential future Labor Leader. Shorten denied this speculation, and was promoted to the Cabinet as Minister for Financial Services and Superannuation. In 2011, he was also given the position of Minister for Workplace Relations.

In 2013, after being elected as leader of the Australian Labor Party, Shorten publicly identified himself as the senior ALP figure at the centre of an allegation of rape said to have occurred in 1986. Shorten strongly denied the allegations. After Victoria Police investigated, the Office of Public Prosecutions advised there was no reasonable prospect of a conviction and no charges were laid.

In early 2015, leading up to Australia Day, Shorten called for a new push for Australia to become a republic. Former ARM chair Malcolm Turnbull said upon his appointment as Prime Minister in September of the same year he would not pursue “his dream” of Australia becoming a republic until after the end of the Queen’s reign, instead focusing his efforts toward the economy. In July 2017, Shorten revealed that should the Labor Party be elected to government at the 2019 federal election, they would legislate for a compulsory plebiscite on the issue. Should that plebiscite be supported by a majority of Australians, a referendum would be held, asking the public for their support for a specific model of government.

In 2015, Shorten said that the voting age should be lowered to 16. In February 2016, Shorten called Cory Bernardi a “homophobe”. In March 2016, Shorten committed that the party would oppose any effort to extend discrimination law exemptions to allow people who object to same-sex marriage to deny goods and services to same-sex couples.

In 2016, Shorten led Labor to gain 14 seats at the federal election when Malcolm Turnbull and the Liberal-National Coalition retained majority government by a single seat. The result was the closest since the 1961 federal election.

Shorten led Labor into the Australian federal election in 2019. Labor had led most polls for the better part of two years, particularly after a series of leadership spills knocked the Coalition down to a predicted minority government.

Shorten announced his resignation as Leader of the Labor Party on 18 May 2019, following Labor’s unexpected defeat in the 2019 election. The day after, Anthony Albanese announced his candidacy in the subsequent leadership election. On 21 May, Chris Bowen announced he would also contest the ballot; however, the next day, he announced his withdrawal, citing his lack of support among the party membership. With no other candidate stepping forward, Albanese took the leadership unopposed on 30 May, with Richard Marles as his deputy.