Who is New Zealand Prime Minister Jacinda Ardern - the world's youngest female leader?

New Zealand's newly sworn-in prime minister, Jacinda Ardern Credit: AP

Jacinda Ardern was officially sworn in as the Prime Minister of New Zealand this morning, promising to form an "active" government that would be "focused, empathetic and strong". 

At 37, Ardern is the youngest New Zealand PM in 150 years, and the country's third woman leader.

She also happens to be one of the few politicians globally to talk openly about mental health, and her personal struggle with anxiety, and is a strong supporter of women's rights and LGBTQ issues. 

She had been tipped for the top for some time, but has spoken about how her crippling anxiety made her worry she wouldn't be suitable to hold the highest office in the country. Her reticence vanished when, eight weeks before the election, her party (New Zealand Labour) was forced into leadership chaos when leader Andrew Little stood down, and Ardern (who had served as his deputy) was unanimously elected to the leadership by her colleagues. 

“There will be good days and there will be bad days," she said in her address this morning. "So, ladies and gentleman, without further ado, let’s go and do this.”

Here's everything you need to know about New Zealand's new Prime Minister.

Ardern is mobbed by university students during a visit to Victoria University in Wellington Credit: AFP

1. She started 'Jacindamania'

Ardern oversaw a remarkable turnaround in her party's fortunes, as her charismatic, relaxed demeanour captured the nation’s attention in a phenomenon that became known as “Jacindamania”.  

Her supporters say that her natural charisma is undeniable - she's New Zealand's answer to Justin Trudeau or Emmanuel Macron, with youth, good looks, and small town charm in abundance. 

But while this portrayal of Ardern may be superficial, it's true to say she ran a positive campaign and has a gift for making people warm to her. At a rally ahead of the election, she told an audience her mother had slipped snacks and a note of encouragement in her bag that morning – something she hadn’t done since Ardern was 10.

It's a folksy, 'just like you' approach that British politicians, arguably, wouldn't get away with on this level - it feels a little too overdone (she constantly references her student job in a fish and chip shop). But it seems to have seduced the voters of New Zealand.

2. She's up to the challenge 

Ardern began her career as a researcher for former PM Helen Clark, an experience which she has said made her wary about the demands of the top job. She later worked in the UK as a policy adviser to Tony Blair, while he was PM. 

In 2008, she became a list MP (a position in New Zealand politics where someone is elected from a party list rather than a geographical constituency. Their presence in Parliament is owing to the number of votes that their party won, not to votes received by the MP personally), before being elected to represent a constituency in February this year.

She became party leader in August.

3. She isn't afraid to talk about mental health

For years, Ardern said she wasn't interested in leading her party, let alone the country. In a matter of weeks, she has accomplished both. 

Her main reason for not wanting the top job was concern that her anxiety would make it difficult for her to cope with the heavy burden of high office. As recently as June, she said she was not cut out to be Labour leader: “When you’re a bit of an anxious person, and you constantly worry about things, there comes a point where certain jobs are just really bad for you," she said.

In an interview with The Guardian last month, Ardern said she no longer believed that, saying: "You can’t ask other people to believe you and vote for you if you don’t back yourself. Every day is the proof point that I’ve got what it takes to do this."

So how is she coping? By ceasing to read her own media coverage, and bolstering herself for the challenge. “I set quite high expectations. So do a lot of people. For what I do, is the experience that I have [of anxiety] normal? Probably. 

“But as with every stage of this job that I’ve been in, I’ve simply thrown myself into it and every time just had the belief that I’ve got what it takes and just powered through, and that will take me right through to the top job.”

4. She has a strong record on LGBTQ issues

Ardern was raised a member of the Mormon Church, but left in 2005 because it conflicted with her personal views, in particular her support for gay rights. 

She voted in favour of the 2013 Marriage Equality Bill, allowing same-sex couples to legally marry in New Zealand. 

New Zealand elects youngest leader for 160 years
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5. She pushes women's issues 

Ardern is a supporter of the liberalisation of abortion law, and advocated for the removal of abortion from the New Zealand Crimes Act.

She has also committed to having 50 per cent of her caucus made up of women. “I have great ambition as a woman and as prime minister elect that we will make great gains as a government in issues like equal pay, in issues like supporting women in the roles they choose to take, whether they be work or in caring roles," she said last week. "I hold that issue close to my heart.”

6. She won't be pushed around

Just a few hours after she was elected Labour leader, Ardern was asked about her plans for motherhood (she doesn't have kids but has spoken openly about how her desire to have a family has made her think twice about taking on high office). 

“I decided to talk about it, it was my choice, so that means I am happy to keep responding to those questions,” said Ardern.

But she passionately defended the right of New Zealand women to keep their child-bearing plans private from their employer: “It is totally unacceptable in 2017 to say that women should have to answer that question in the workplace, it is unacceptable, it is unacceptable.

"It is a women’s decision about when they choose to have children and it should not predetermine whether or not they are given a job or have job opportunities.”