Among these classified documents was a notorious video showing US troops firing on Iraqi civilians, the so-called ‘Collateral Murder’ video which showed footage from a 2007 Baghdad airstrike that killed Iraqi journalists, among others.
Speaking in 2011 to SBS’s Dateline program, Mr Assange said he wanted to hold governments and military forces to account.
"This is 91,000 reports between 2004 and 2010 from US forces - not generally including Special Forces, but all regular US Army forces in Afghanistan,” he said. “And it includes the location, date, the unit involved, the number of people killed, wounded or detained. In fact, it's the most detailed history of any war [that] has been made ever. It's significant."
The leaking of classified documents may be punished by up to 45 years in jail under the US Espionage Act.
Julian's mother, Christine Assange, told SBS that same year the Gillard Labor government should do more to help her son, accusing it of being a "puppet" of the US.
"It would appear that the only person that the government listens to, at least Julia Gillard, is Barack Obama,” Ms Assange said. “It would appear that we aren't really a country at all in our own right, we have no independence and that we're just fast moving from being a colony of the Commonwealth to being the 51st state of the US. So I don't know what's going to happen."
What is WikiLeaks?
Mr Assange founded WikiLeaks in Iceland in 2006, as a non-profit website which claims to have since published more than 10 million classified or censored documents, protecting the sources of the leaks with anonymity.
Some of its many document releases include the 2010 US State Department classified diplomatic ‘cables’ which embarrassed many countries.
Wikileaks calls itself a "multinational media organisation and associated library" and Mr Assange its publisher.
But the group’s methods have been criticised by some traditional media outlets for dumping huge tranches of documents online without regard for the safety risks to individuals named in the documents.
The 'Collateral Murder' document dump also led to the jailing of US Private First Class Bradley Manning, now known as Chelsea Manning, whose sentence was eventually commuted by then-US President Barack Obama after serving about seven years for her role in the leaks.
Allegations of Russian collusion
While some see Assange as a free speech advocate and exposer of secrets, others consider him an enemy of the state.
In 2016, the United Nations declared Mr Assange had been arbitrarily detained by Sweden and the United States, calling on authorities to end his "deprivation of liberty".
His confinement did little to stop the flow of documents from WikiLeaks. In the lead-up to the 2016 US Election, the organisation released emails and documents from the Democrat Party, potentially damaging Hillary Clinton's campaign.
Ms Clinton alleged to the ABC last year that Mr Assange colluded with a Russian intelligence operation to disrupt the election and damage her candidacy for president.
"Assange has become a kind of nihilistic opportunist who does the bidding of a dictator," she said. "WikiLeaks is unfortunately now practically a fully owned subsidiary of Russian intelligence."
In response to her comments, Mr Assange tweeted that Ms Clinton was "not a credible person".
In January of this year, Ecuador announced it was making Julian Assange a citizen. Ecuador foreign minister Maria Fernanda Espinosa, said her country must do the right thing.
"The problem here of the asylum seeker is not the issue of facing British law. That's not the issue," she said. "It's founded fears that we have about possible risks to the life and integrity of Citizen Assange, not necessarily from the United Kingdom but possibly by third states."
Swedish prosecutors dropped the assault charges in May 2017, along with a European Arrest Warrant. Despite this, British police had vowed they would still take him into custody if he attempted to leave the embassy.
Julian Assange: Timeline
- 3 July 1971 - Born in Townsville, Queensland.
- 1987 - Begins hacking under the name ‘Mendax’.
- December 1996 - Pleads guilty to hacking charges in Australia, receives fine.
- December 2006 - Founds WikiLeaks in Iceland.
- April 2010 - WikiLeaks publishes classified US Chelsea Manning material.
- May 2010 - Manning arrested in the US, Assange named as a person of interest in case.
- August 2010 - Assange visits Sweden, is accused of sexual assault by two women.
- December 2010 - Assange wins Time readers’ poll for Person of the Year.
- June 2012 - Assange goes to Ecuadorian embassy in London and claims political asylum.
- February 2016 - UN Working Group declares Assange was subject to arbitrary detention by Swedish and British governments.
- July 2016 - WikiLeaks publishes Secretary of State emails from Hillary Clinton’s private email server during US Election campaign.
- 19 May 2017 - Swedish authorities drop their investigation into Assange.
- January 2018 - Ecuador makes Assange a citizen.
- 7 February 2018 - Ruling on Assange’s UK arrest warrant.