Jacinda Ardern promised "relentless positivity" as New Zealand's prime minister, but in announcing her shock resignation on Thursday admitted the unrelenting demands of the job had finally worn her down.
A fresh-faced Ardern was elected prime minister in 2017, and in a tumultuous first term faced New Zealand's worst terror attack, a deadly volcanic eruption, and the Covid-19 pandemic.
Just 37 years old at the time, she became the country's youngest prime minister since 1856 and a global icon for progressive politics.
Ardern won a landslide second term in 2020, but her popularity has been on the slide as she battles declining trust in government, a deteriorating economic situation, and a resurgent conservative opposition.
The stress has been evident in recent months -- Ardern showing a rare lapse of poise when she was unwittingly caught on microphone calling an opposition politician an "arrogant prick".
"This has been the most fulfilling five and a half years of my life. But it has also had its challenges," Ardern, 42, said on Thursday.
"I know what this job takes, and I know that I no longer have enough in the tank to do it justice. It is that simple."
She had been in office barely 18 months when a white supremacist gunman opened fire in two Christchurch mosques during Friday prayers, killing 51 Muslim worshippers and wounding another 40.
Her deft and compassionate response to the rampage of hate defined the charismatic centre-left leader's image around the world.
When she donned a headscarf and comforted victims' families after the shooting, it resonated globally.
She would later describe it as a spontaneous gesture of respect to the Muslim community.
Ardern also won plaudits for decisive policy action, including swiftly enacted gun law reforms and a push to force social media giants to address online hate speech.
The New Zealand public emphatically backed her performance, giving her a second three-year term in October 2020.
Ardern's campaign pitch focused heavily on her government's success in containing the coronavirus.
Life within New Zealand has largely returned to normal after a series of strict lockdowns.
- 'Jacinda-mania' -
Ardern grew up in the North Island hinterland, where her father was a police officer.
She credits the poverty she saw there with shaping her beliefs.
Raised as a Mormon, Ardern left the faith in her 20s due to its stance against homosexuality.
After completing a communications degree, Ardern began her political career in former prime minister Helen Clark's office before heading to Britain to work as a policy adviser in Tony Blair's government.
She was elected to parliament in 2008 and in March 2017 became Labour's deputy leader, saying at the time that she was not ambitious and saw herself as a backroom staffer.
Ardern transformed from self-described "policy nerd" to prime minister on a wave of "Jacinda-mania" after being thrust into the Labour leadership just seven weeks before the 2017 election.
She made headlines again a year later when she became only the second prime minister in the world to give birth while in office -- after Pakistan's Benazir Bhutto in 1990.
Her baby, Neve, is due to start school later this year.
After Christchurch, she again offered comfort to the nation, when the White Island (also known as Whakaari) volcano erupted, killing 21 people and leaving dozens more with horrific burns.
Ardern has constantly urged New Zealanders during the coronavirus crisis to "be kind", appealing for a unified approach from what she terms a "team of five million".