Revellers of all ages – many in fantastic costumes – danced to Donna Summer’s I Feel Love in the minutes beforehand.
The classic disco track, chosen by the public, was also played simultaneously at family-friendly events across the region.
Earlier fears that rain and wind could stop the ball being raised at all were soon forgotten as the spinning ball glittered under the sun breaking through the clouds.
But a slight delay for health and safety reasons meant the countdown to the much-anticipated moment had to take place after the chosen track had finished.
The event, which is part of the Yorkshire Festival, kicked off at 3pm with attractions including street theatre performances, a family photo booth, temporary tattoo parlour, glitter stations, a DJ school and street good stalls.
Catherine O’Melia, 42, brought along daughter Grace, six, and son Victor, four, to enjoy the party with their friends.
She said: “We love disco and as soon as I heard the biggest disco ball in the world was coming to Leeds, I thought ‘I have to be there!’”
Wayne Thackwray was there with his wife, Caroline, and their two children, Carys and Bryony.
“To start with it wasn’t too busy, but the atmosphere is very good,” he said. “There’s lots for the kids to do, Bryony has been DJing.
“It really puts Leeds on the map. If the weather was good we’d be back again.”
Will Scollie, who has just moved to Leeds from London with wife Claire, was among the revellers pleased to see the disco ball make it up in the air.
He said: “It’s not a disco ball if it’s not up in the air and spinning! It’s been a really good atmosphere. The fact lots of people have dressed up and got face paint on is really good.”
On the disco track choice, Claire added: “I was pleased with the choice but I thought it would probably be We Are Family, which we heard when we were arriving earlier.
“Now that the balls is up we’re very impressed. I think it looks great.”
Thousands of revellers are expected to join the giant street party on the edge of the city centre as it continues into the early hours.
BBC 6 music DJ Craig Charles had been due to play a set but had to cancel this morning after being involved in an accident.
He was replaced by DJ Yoda, who tweeted: “Never DJ’d in a city centre at 7.30pm on a Friday night before! LEEDS - I’m getting ready to rock the brexit out of you!”
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