The boys won best pop video, best new artist and most share-worthy video.
"We've grown up watching this show and to even be here is an honour," Niall said from the stage.
As he went up to accept the award for best pop video for their song What Makes You Beautiful, the cheeky Mullingar lad swooped in for a kiss with presenter Katie Perry.
The VMAs are famous for the odd jaw-dropping kiss -- most notably the steamy kiss between Madonna and Britney Spears in 2003.
But last night it was the blond Irish teen who stole the headlines -- and close pal Demi Lovato also got kissing, this time her statuette for Best Video with a Message.
One Direction beat Justin Bieber and Rihanna for best pop video, and fellow all-boy outfit The Wanted as best new artists.
The group performed later, rising to a stairwell surrounded by screaming, reaching female fans on an elevated platform and bringing the crowd to their feet.
"This has been unbelievable," Harry Styles said backstage. "This was our favourite performance we've ever done. For us to be here in the first place is amazing, and to perform and win a Moonman is amazing."
One Direction drew the loudest cheers of the day -- something even rivals The Wanted acknowledged -- even though fans had to sweat under scorching heat to get a glimpse of the stars.
The event was full of highlights. Pink floated above the crowd on a pair of oversized lips as she performed her new song Blow Me (One Last Kiss) before Frank Ocean wowed with a sombre, moonlit version of Thinking About You.
Then there was Olympic champion Gabby Douglas flipping on stage to new Alicia Keys song Girl On Fire, and Taylor Swift dived into the crowd after a group sing-a-long of her new hit We Are Never Ever Getting Back Together.