The horrific events of last Friday were unprecedented for a small country like New Zealand - 50 people killed in a terrorist attack.
In the Prime Minister's own words, she took on a role she "never anticipated having" which was to "voice the grief of a nation".
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Jacinda Ardern has been recognised for standing strong since the attack, with commentators worldwide praising her humanity and integrity.
From pledging to never speak the alleged gunman's name, to banning military-style semi-automatic weapons, below is a timeline of the Prime Minister's actions since that day.
Friday, 15 March
As the scale of the attack unfolded, Ardern labelled the Christchurch shootings "one of New Zealand's darkest days".
"This is an act that has absolutely no place in New Zealand - this is not who we are," she said.
The National Security System was initiated, and Ardern flew to Wellington that evening for an emergency meeting at Parliament's bunker.
That night, she confirmed 40 people had been killed in the shooting.
She said it could "only be described as a terrorist attack".
"You may have chosen us but we utterly reject and condemn you," she said.
Saturday, 16 March
On the same morning the 28-year-old shooting accused appeared in Christchurch District Court, Ardern arrived in the city.
She wore a hijab when she and leaders from other political parties met with relatives and friends of those caught up in the attacks.
An image of the Prime Minister wearing the hijab, taken by Kirk Hargreaves, was widely shared online.
Ardern foreshadowed that New Zealand's gun laws would change in light of the attack.
She confirmed US President Donald Trump had called to offer condolences, and was pointed in her response to him.
"He asked what offer of support the United States could provide - my message was sympathy and love for all Muslim communities," she said.
Sunday, 17 March
The Prime Minister's response to the attacks was praised by world media.
It was revealed the alleged killer had emailed Ardern a copy of his white supremacist manifesto just minutes before the attacks.
Ardern returned to Wellington, where she met with the Muslim community at the Kilbirnie mosque, again wearing a hijab.
Images of her hugging and comforting the community were shared worldwide.
The Prime Minister said her Cabinet would meet on Monday to discuss possible gun law changes.
She announced the Government would cover the cost of funerals for families of the victims.
Monday, 18 March
The Prime Minister said changes to gun laws were coming and that the cabinet had agreed in principle to what those changes would be, announcing more details would follow.
National Party leader Simon Bridges pledged his party's full support.
Ardern, supported by Police Commissioner Mike Bush, announced an inquiry into the alleged gunman's activity leading up to the attacks.
She said the were would be a national day of mourning for New Zealand.
Ardern's leadership was praised in an article by The Guardian, for "showing the world what real leadership is.''
Tuesday, 19 March
The Prime Minister addressed concerns over the alleged gunman's livestream video.
She joined other world leaders in calling for technology giants to take accountability for the content they facilitate.
"We cannot simply sit back and accept that these platforms just exist and that what is said on them is not the responsibility of the place where they are published," she said. "They are the publisher. Not just the postman."
Ardern, along with the leaders of all other political parties in Parliament, paid respects to victims in a special session.
In her speech, Ardern condemned the shooter: "You will never hear me mention his name. He is a terrorist. He is a criminal. He is an extremist. But he will, when I speak, be nameless."
Ardern implored New Zealanders to do the same: "Speak the name of those who were lost, rather than of the man who took them."
She spoke about taking on a role that she "never anticipated having, and hoped never to have".
That role has been to "voice the grief of a nation".
Wednesday, 20 March
The Prime Minister touched down in Christchurch for her second visit since attacks.
She visited Cashmere High, the school which two of the terror attack victims had attended.
"Events like this; these are not things New Zealand has ever experienced before. These kinds of things don't happen here, where we live," she said.
She urged students to make use of the 1737 helpline.
The Prime Minister then met with first responders from the attacks.
In a meeting with St John staff who had been the first on the scene, she commended their professionalism and said they had saved lives.
In Wellington, National MP Judith Collins praised Ardern's leadership during a speech in Parliament and defended her wearing a hijab.
Ardern was asked in Christchurch about threats made by Islamic State calling for retaliatory attacks.
"What I've heard from the Muslim community [is] the rejection of extremism, violence and hate, no matter where it comes from," she said.
When asked if New Zealand could be a "blueprint" for other countries to follow in how it tackles gun control, Ardern flipped the question.
"I guess if I was to say New Zealand is a blueprint for anything, in some ways it's a blueprint [for] not what not to do. My hope is that going forward we will demonstrate what you can do if your starting point is similar to ours."
Her leadership was commended in an opinion piece for The Washington Post by Turkey's President Recep Tayyip Erdogan.
During an interview with the BBC, Ardern said the alleged gunman's ideology came from overseas.
"What New Zealand experienced here was violence brought against us by someone who grew up and learned their ideology somewhere else."
Thursday, 21 March
Government Communications Security Bureau (GCSB) Minister Andrew Little said multiple reviews into New Zealand's spy agencies may be necessary because the alleged gunman was not on any watchlist.
A cartoon in The Washington Post contrasted Ardern's response to the terror attack with that of Trump - alluding to her quick action on gun law reform.
In an interview with Al Jazeera, the Prime Minister said: "We reject extremism and violence in all its forms."
Ardern announced the Government would ban military-style semi-automatic weapons and assault rifles, high-capacity magazines, and anything that can modify weapons into have a semi-automatic capacity.
"On 15 March our history changed forever. Now, our laws will too. We are announcing action today on behalf of all New Zealanders to strengthen our gun laws and make our country a safer place."
US Presidential Democratic candidate Bernie Sanders praised New Zealand's quick response to the Christchurch attacks, as did Democrat Alexandria Ocasio-Cortez.
Ardern announced a nationwide reflection for the victims to be held on Friday at 1:30pm.
An article in Vogue labelled Ardern "a leader for our time".