He was a member of the Parliament of Western Australia from 1959 to 1984, and a minister in the governments of David Brand and Charles Court.

The 1983 state election occurred 13 months later, in which the O'Connor government was defeated by Brian Burke and the Labor Party.

[3][9] O'Connor played sports as a teenager and young adult, winning state titles in athletics for hurdles and discus in 1943.

After doing jungle training in Canungra, Queensland,[10] he embarked at Brisbane on 5 June 1945 and disembarked at Torokina on the island of Bougainville five days later, where he was transferred to the 61st Battalion.

[3][10] After encouragement from his father, O'Connor contested the Metropolitan Province of the Western Australian Legislative Council at the 1956 state election as an "independent Liberal" candidate, receiving 884 votes out of 15,159.

[21] He said that although he personally opposed compulsory seatbelts as an "infringement on individuals' rights", cabinet approved it so he had to introduce the legislation for it.

In February 1970, he travelled on the inaugural Indian Pacific train from Sydney to Perth, a journey only made possible by the gauge standardisation.

A group of MPs put O'Connor forward as a token candidate to make sure that Court did not take the leadership for granted.

O'Connor indicated he would accept the nomination, but declined during the party room meeting, so Court was elected unopposed.

[27] Two years later, the Liberals won the 1974 state election, and formed a coalition with the National Country Party, led by Ray McPharlin.

[32] O'Connor was the police minister when the murder of well known socialite and brothel keeper Shirley Finn occurred on 22 June 1975.

[21][35] A coronial inquest was held between 2017 and 2019 which heard evidence that she was bribing the police to avoid having her brothel shut down, and that she threatened to blow the whistle on the persons involved unless she had her large tax bill paid.

[35] Another witness alleged that O'Connor was the person who actually carried out the murder,[40][41] but the coroner ruled out his testimony due to several inconsistencies.

[46] O'Connor objected to immigrants coming to Australia without any check for criminal records or their health, and said that "we should give them money, petrol, turn their boat round and send them home".

[48][49] O'Connor retained the labour and industry, consumer affairs, and immigration portfolios, and gained regional administration and the north-west, and tourism.

[48] In anticipation of Court retiring soon, O'Connor would take Liberal MPs out to dinner, sometimes offering them ministries if they voted for him in a leadership election.

According to Tony Warton, Court's media advisor, his preferred successor was Peter Jones, a National Country Party minister.

[59] Soon after becoming premier, O'Connor sacked more than 200 workers at the Hospital Laundry Linen Service for striking and threatened to deregister their union.

[55][61] Later in February, the government approved a pay rise for nurses, who had been part of a prominent campaign against depressed wages a year previously.

[55][62] On 31 July, another by-election occurred for the North Province following the resignation of Liberal turned independent MLC Bill Withers.

With the federal government unpopular, he asked for Prime Minister Malcolm Fraser to stay out of the campaign, saying "'we can run our own show and don't need any help or hindrance from Canberra".

[65] By early 1984, O'Connor was encountering pressure to resign as his media and parliamentary skills were no match for Burke's,[70][71] and he had taken a six week family holiday to Europe at the end of 1983.

[80][81] Burke resigned as premier in February 1988 and was replaced by Peter Dowding,[82] who himself resigned in February 1990 amid unpopularity due to the WA Inc scandal,[83] a series of controversial government investments and deals with private enterprise dating back to the Burke government.

It was alleged that Bond Corporation was bribing Stirling councillors in 1984 to approve the Observation City hotel development in Scarborough.

[89][90][91] The commission was played a recording of the conversation secretly taped by Terry Burke where O'Connor said he was given a $30,000 bribe by former Bond Corporation managing director Peter Beckwith on behalf of subsidiary Austmark International.

[96][97] In the same month, the commission began investigating O'Connor's finances, suspecting him of having stolen a $25,000 cheque from Bond Corporation in April 1984.

The cheque was made out to a "Mt Lawley campaign fund" and recorded by Bond Corporation as a political donation.

[100] Unrelated to the cheque, the investigation found that O'Connor had not paid tax on the $500 per week he received from Connell for his consultancy business.

[101][102] The report stated that "O'Connor was given every opportunity to explain the source of the sum deposited to the credit of his account on 19 April 1984, but was unable to do so in any believable way.

"[117] O'Connor married his first wife Beverley Vilma Lydiate, with whom he had four daughters and four sons, at St Francis Xavier's Church in East Perth on 17 June 1950.