O'Neill's father moved to Papua New Guinea in 1949 as an Australian government field officer (also known as a kiap) and later served as a magistrate in Goroka until his death in 1982.

O'Neill spent the first years of his youth in his mother's village, and after attending secondary school, he stayed at his father's urban residence in Goroka.

Later that year, O'Neill became leader of the opposition, but Speaker Jeffery Nape initially did not recognise him and claimed Peter Yama held the position instead.

The Supreme Court ruled that Somare was the legitimate prime minister, but O'Neill retained overwhelming support in parliament.

[21] O'Neill resorted, as before, to parliamentary rules to procrastinate the vote of no confidence and suggested adjourning parliament for three weeks.

[24] The political configuration changed fundamentally when William Duma and the Natural Resources Party made a deciding move and joined the opposition.

[30] O'Neill then avoids a vote of no confidence by following the suggestion that he had rejected earlier: he resigns and appoints Julius Chan as his successor.

O'Neill resigned again and handed over to Marape as prime minister, in line with the constitutional requirement that the largest party form the government.

[40][41] The international stature of PNG was raised through the organisation of the 2015 Pacific Games,[42] and the proposal of Port Moresby as the location for the APEC summit in 2020.

The public holiday was established at the request of a "group of churches", which had approached Abal with the idea shortly before he lost his office.

[55] Hosting the Asia-Pacific Economic Cooperation (APEC) meeting in 2018 was a highpoint in international relations for O'Neill as prime minister.

Chinese officials were escorted out of the building by security when Rimbink Pato, the PNG minister of foreign affairs, was drafting a final communiqué with his staff.

[57] The expenditure for this conference, especially the purchase of a fleet of Maserati and Bentley motorcars, played a role in the ousting of O'Neill as prime minister.

[65] The commission of inquiry in the National Provident Fund of 2003 recommended prosecuting O'Neill for extorting money in return for revaluing a contract to build a high-rise.

[67] O'Neill's name was involved in an enquiry into the irregular disbursement of massive legal fees to the law firm of Paul Paraka.

[68] Another irregular payment of 31 million Australian dollars occurred after the government apparently cut ties with Paraka lawyers when O'Neill was Prime Minister.

[71][72] O'Neill nationalised the Ok Tedi Mine owned by the PNG Sustainable Development Fund (PNGSDF) without compensation.

The O'Neill government had stated after taking power in 2012 that it intended to obtain a bigger share of dividends from the mine, but nationalisation without compensation came as a surprise.

[80] Greg Sheppard, a lawyer close to O'Neill, has been charged with defrauding a trust fund established to aid communities impacted by the OkTedi mine.

[82] He also faced an alleged disregard for regulatory control and political procedure in arranging a loan from the Swiss banking firm UBS to obtain shares in Oil Search.

[84] O'Neill's lawyers challenged the powers of the Ombudsman to investigate the Prime Minister as well as publish and distribute the resulting information.

[87] Prime Minister Marape has installed a Commission of inquiry under the leadership of the chief justice and with the head of the anti-corruption Task force, Sweep, as council.

[99] Faced with declining revenues, falling business confidence, and poor prospects for recovery, a challenge to his leadership became inevitable.

That is most notable and controversial with respect to the UBS loan meant to acquire interests in the Elk Antelope gas field through a shareholding in Oil Search.

He considers the negative view of the PNG economy to be IMF-inspired, and the budget is made up by foreign academics who had not even lived in the country.

O'Neill predicted that "it will not be long before Morauta and Opposition Leader Patrick Pruaitch join government so be prepared to make way for them.

Second, he accuses the Marape government of giving a false negative picture of the economy inspired by outsiders, including the Australian economist Paul Flanagan and the IMF.

[109] He was arrested shortly after returning on 23 May 2020, again on charges of official corruption, stemming from the purchase of two generators from a company in Israel with which he was accused of having close ties.

[115] In reply to a question by the MP Gary Juffa in 2019, it was stated that the diesel generators were too expensive to run for PNG power and that only one was serviceable.

[119] The vote of no confidence foundered because the opposition appeared to be too fragmented in its choice of alternate prime minister to muster a majority.