At the
2017 election, McGowan led the Labor Party to one of its most comprehensive victories at either the state or territory level since Federation. Labor won 41 of the 59 seats on 55.5 percent of the two-party vote, the largest majority government in Western Australian history. Labor also took 20 seats off the incumbent Liberal
National government on a swing of 12.8 percent, the worst defeat of a sitting government in Western Australian history. Seven members of Barnett's cabinet were defeated, including Nationals Leader
Brendon Grylls. His own margin in Rockingham swelled from an already comfortably safe 13.2 percent to 23.4 percent. McGowan's win was built primarily on the strength of a dominating performance in Perth. Labor picked up a swing of 13.6 percent in Perth and took all but nine of the capital's 43 seats, accounting for almost all of its majority. According to
Antony Green of
ABC News, the 10-point swing Labor theoretically needed to win was not as daunting as it seemed on paper. Besides the
one vote one value reforms in 2008 that allowed Perth to elect over 70 percent of the legislature, much of the Liberals' 2013 margin was built on inflated margins in Perth's outer suburbs. Early in his premiership, McGowan moved to limit the number of pathways for foreign workers to enter the state, re-committed to terminating the controversial
Perth Freight Link highway project, which had proved extremely unpopular in large parts of the state, and he restructured various government departments. McGowan also introduced unlimited fines and life imprisonment for people deemed to be trafficking methamphetamine, and worked to expand Chinese investment in Western Australia. On 1 May 2018, Kim Beazley was sworn in to a four-year term as governor upon the recommendation of McGowan. He was the first ex-politician to become governor since
Sir James Mitchell in 1948. His appointment was generally well received, although some people had reservations that a
republican had become the Queen's representative and that Beazley was close friends with McGowan. McGowan had
ministerial responsibility for the
Perth Mint between the 2017 and
2021 elections. In 2018, the Mint commenced doping its gold bars with lower value metals. The Shanghai Gold Exchange later discovered that some of the gold it bought from the Perth Mint contained more silver than was allowed under its standards. The Perth Mint covered this up when alerted and it was only made public by an ABC
Four Corners investigation. The Mint has also been under investigation by
AUSTRAC for having potentially breached anti-money laundering laws.
Response to the COVID-19 pandemic (2020–2021) Throughout 2020 and 2021, McGowan led
Western Australia's response to the
COVID-19 pandemic. He acted early to close the state's borders to the rest of the country on 5 April. In July 2020, businessman
Clive Palmer claimed that the closing of the borders was
unconstitutional and launched
a legal challenge in the
Federal Court. The case was defeated, and in response McGowan labelled Palmer an "
enemy of the state". Shortly afterwards, McGowan's popularity in opinion polls dramatically increased, reaching 91% approval in September 2020, a record for any Australian premier. In March 2021, he suggested that some internal Australian border controls could be continued after the pandemic, on the grounds that they had helped to keep illegal drugs out of Western Australia, but clarified later that he meant to suggest only an increased police presence at border checkpoints, rather than completely sealing the border.
2021 election In the lead up to the
2021 election, WA Labor raced out to a large lead in opinion polls, leading to speculation that the McGowan Government would be reelected with another record majority. Labor approached 70% in the two-party preferred polls, with McGowan maintaining a personal approval rating of 88%. Opposition Leader
Zak Kirkup took the unprecedented step of conceding the election more than a fortnight before election day. On 13 March 2021, WA Labor won the most comprehensive victory, in terms of vote share and percentage of seats controlled, at any level in Australia since Federation. Labor took 69.7 percent of the two-party vote and picked up a 13-seat swing, ultimately winning 53 out of 59 seats, including all but one in Perth. Labor even managed to defeat Kirkup in his own seat. McGowan announced the formation of a panel to examine potential reform of the
Western Australian Legislative Council voting system soon after the 2021 election, after denying he would implement reforms to the Legislative Council voting system several times during the election. The panel was led by former
Governor of Western Australia Malcolm McCusker, and consisted of four electoral and constitutional law experts. McGowan and Electoral Affairs Minister
John Quigley said the election of
Wilson Tucker with 98 primary votes was a key reason for their change of mind. In September 2021, McGowan announced the changes to be made to the voting system, including abolishing regions in the Legislative Council, and removing
group voting tickets. Also that month, he handed down the Western Australian state budget, which recorded a sizeable surplus of $5.6 billion. On 13 December 2021, McGowan announced that Western Australia would fully open its borders to COVID-19 vaccinated people from interstate and overseas on 5 February 2022. On 20 January 2022, McGowan reversed his decision on the plan for Western Australia to fully open its borders, saying that the
Omicron variant of COVID-19 was more contagious than previous variants of the virus and that the state's vaccination booster levels were not high enough to safely reopen to the world. A February opinion poll showed that his approval rating had decreased to 64%, the lowest during the pandemic, but still comparatively high to premiers in other states. On 18 February, McGowan announced the border would reopen on 3 March for people from outside Australia and triple vaccinated people from interstate. When Beazley's term as governor finished in 2022, McGowan recommended WA Police Commissioner
Chris Dawson as his replacement. Dawson was sworn in on 15 July 2022.
Resignation and retirement from politics On 29 May 2023, McGowan announced he would step down as premier and member for Rockingham. He cited his exhaustion from the relentless pressures of the job as the reason for his resignation. In her valedictory speech in the Legislative Council in April 2025, retiring senior frontbencher
Sue Ellery stated, "I was distressed when Mark decided to step down as Premier," and said that she and a number of other colleagues had "begged him not to go". McGowan went on leave following Friday 2 June, and formally resigned on Thursday 8 June. A
leadership election of the Labor Party caucus was held decide his replacement. Despite initially being a three way contest between Roger Cook, Rita Saffioti and
Amber-Jade Sanderson, both Saffioti and Sanderson withdrew leaving Cook as the only nominee, he was subsequently elected to succeed McGowan, with Rita Saffioti as his deputy. == Career after politics ==