It's also a coup to be able to look interested and enthused the entire time at what must have, at some points, been deadly dull. She pulled off what Camilla couldn't at the Commonwealth Games opening.
Double coup to do all of that while almost seven months pregnant - yes I know it's not a disability or an illness, it's just a pregnancy, but it doesn't mean it's not tiring.
The other achievement for Ardern was seeming at ease and respectful around the royals. Notably, the Queen.
For a woman who believes we will see New Zealand become a republic in her lifetime, she sashayed through Buckingham Palace and conducted her toast at the state banquet like it was the most natural thing in the world. She even managed to publicly support Prince Charles as head of the Commonwealth.
The British and European press, though not really that interested in New Zealand's Prime Minister, did manage to say positive things when they did refer to her. That kind of coverage always makes Kiwis feel proud, and Jacinda herself will be pleased that after the ugly few weeks she'd endured here at home before she left, that she's been able to impress on the world stage.
Nothing tangible comes out of Chogm of course, well not for a few years anyway, but the positive 'buzz' around it, is all you can really hope for. She didn't trip up, embarrass us, say anything awkward, or wear her Allbirds in public view.
She encapsulated all the key ingredients to woo a swooning press: female, young, pregnant, smiley, upbeat, positive, culturally aware and considerate. Yes it will be a great day when we have evolved enough to be able to take the words 'female, young and pregnant' off the list of notable aspects of her leadership.
But for now, these things are still a big deal. Ardern will be hoping now that the glow of this trip lasts at least another few weeks before she takes maternity leave to have her baby - after which the Jacindamania honeymoon, for the press anyway, will hit its revival once more. Mark my words.