Known throughout British athletics as 'KJT', the gifted Liverpudlian has suffered disappointments and under-performed on the biggest stage, but this time she made no mistake in winning the pentathlon title at the world indoor championships.
With the title coming down to the last of the five events, the 800 metres, Johnson-Thompson raced away from her two nearest rivals, Cuba's Yorgelis Rodriguez and Austrian Ivona Dadic, in the four-lap finale to land the hosts' first gold of the event.
Having been the best long jumper (6.50 metres) and high jumper (1.91 metres) during the day, her victory gave her a total of 4750 points, 50 points clear of Dadic, who could only finish third in the 800, and 113 points ahead of Rodriguez.
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"It's been a long time coming," the delighted Johnson-Thompson told the crowd at Arena Birmingham afterwards, thanking them for having braved the snow storms in the city to watch her.
The last time the 25-year-old Johnson-Thompson contested a pentathlon three years ago, she became European indoor champion with a magnificent 5,000 point performance that was just 13 points shy of Nataliya Dobrynska's world record.
It was supposed to be the signal for this one-time world-beating junior to become the pre-eminent senior woman multi-eventer.
Yet subsequent struggles with her weaker throws and lack of belief in her jumping meant she could only finish sixth in the heptathlon at the Olympics and fifth in last year's world championships in London.
Yet in a second year since moving to France to train under French coach Bertrand Valcin, she consistently looked the class act in a field in Birmingham which did not include Belgium's Olympic champion Nafi Thiam.
"It's been very difficult for me," she explained afterwards. "I had to leave my dogs and my mum back home and it's been very lonely out there in France, with the language barrier there too.
"But this is what I wanted. It's not my personal best but hopefully it can be the start of something."
(Reporting by Ian Chadband; Editing by Toby Davis)
