The 24-year-old from Middlesbrough, without a previous record of achievement and overlooked for the London Olympics, expected no more than to soak up the experience. Instead he emerged last night as the gold medallist after pulling out the most unexpected of victories.
It came amid a flurry that saw Great Britain and Northern Ireland go from empty-handed to full of joy in barely 15 minutes, with Tiffany Porter claiming bronze in the 60m hurdles.
A repeat of her result in 2012, she has some prior form. But Kilty's triumph, secured by a third personal best in three races here on the Baltic coast, offered weight to those who argue even those on the apparent fringes should be given an opportunity to chase their fantasies.
"I can't believe it," he said. "This is a dream come true, a boyhood dream. I told my dad Kevin four years ago that I would be a world champion and to think I've come out and done that, I feel like crying.
"After getting beaten by Nesta Carter in the semi-final, I went back with my coach and he told me where I went wrong. I came and corrected it in the final, ran the fastest time in the championships and became the world champion."
Porter rebounded from a poor start as she fought through to trail Olympic champion Sally Pearson by a tiny margin as Nia Ali of the USA emerged triumphant.
"At the end of the day I'm happy," she said. "It's bittersweet, though, because it wasn't my best race."
If Kilty confounded past form, Valerie Adams lived up to her billing. For the past seven years, the New Zealander has been seemingly invincible in the shot putt and that run continued as the 29-year-old claimed gold for the third successive time, another addition to a wall of honour that includes four outdoor crowns and the Olympic titles garner in London and Beijing.
Her best throw, of 20.67 metres, was one of five attempts which no-one else could surpass. Consistency sets her apart and the Swiss-based Kiwi confirmed she will pursue a hat-trick of Commonwealth titles in Glasgow this summer.
"I really have a passion and a motivation that's really indescribable," she said. "I love training. I love the challenges that come with it.
"I've been doing this for 15 years now. There's not a day that goes by that I don't enjoy it. The day when I wake up and I don't enjoy it, I'm out."
Abeba Aregawi added the indoor world 1500m title to the outdoor crown she picked up last year with the Ethiopian-born Swede leaving her challengers an astounding 6.1 seconds behind.
Francena McCorory won the 400m while American compatriot Ashton Eaton defended his heptathlon title but just missed out on improving his world record, despite a furious push in the concluding 1000m.
The remaining titles go on the line this afternoon. And Eilidh Child will bid to lead by example when she heads the British bid in the 4x400 relay final.
The UK's men will have their own medal shot in their 4x400 final with Jamie Bowie set to learn this morning whether he will have a part to play. The 24-year-old from Inverness was second-quickest among his colleagues as they qualified second behind the USA but with Richard Buck and Nigel Levine available, he knows his place is under threat. "We want the four strongest to go into the final and all seven of us will be behind them," he said.
Jamaica's Veronica Campbell-Brown confessed to ring rust as she advanced into the 60m semi-finals in her first race since she was cleared of a doping charge.
The defending champion, who claims she has "nothing to prove" despite her critics, was only 13th fastest among a list of qualifiers that also included British teenager Sophie Papps and her team-mate Asha Philip.
Holly Bleasdale may be Britain's safest bet for gold today with the pole-vaulter ranked No 1 among those competing.