From about noon, the crowd, estimated by organisers at between 2000 and 3000, spread itself over the lawn in front of the band rotunda and up the side of the nearby hill.
In the heat, unofficially at 30degC in parts of Dunedin, officially 21degC at 2.30pm, according to the MetService, people had anything but the chills, and shady spots were at a premium.
The concert was put on by the Dunedin City Council as part of a series of concerts celebrating the garden's 150th anniversary this year.
The band, which had the crowd on its feet for popular hits Heavenly Pop Hit and I Love My Leather Jacket, appeared to be enjoying themselves as much as the crowd.
Thanking the organisers and those who attended, lead singer Martin Phillipps said he knew park managers Barbara Wheeler and Alan Matchett were a bit nervous about having the concert in the garden.
''But I think it shows just what great events we can have here,'' he said, to a big cheer from the crowd.
The band's manager, Scott Muir, said it was the Chills' biggest crowd in Dunedin for some years.
Dunedin woman Gabby Enright said it had been ''totally'' worth arriving at noon to stake out the perfect position for the 1pm concert. She was a Chills fan from ''way back'', the concert was ''fantastic'' and the garden was a great venue.
Council communications and marketing manager Graham McKerracher said the event could not have gone better.
Free Sunday concerts at the garden will continue until April, with other performers including the Dunedin City Jazz Orchestra, the Otago Symphonic Band and brass bands.
