The psychedelic, 30-piece installation Millbrook Holiday (the League for Spiritual Discovery) was awarded the 2012 Premier Portage Award at a ceremony in Auckland last night.
The $15,000 award is the country's most valuable pottery prize.
"I'm stunned - stunned and surprised," Cooper said from the awards ceremony last night.
"There's so much talent among these finalists. I still feel a little stunned. It's very, very exciting."
And he already had plans for the prize money.
"There will be a few people who will be pleased that I can pay their bills now," he said.
Judge and Oslo National Academy of the Arts professor of ceramic art Dr Paul Scott described the winning creation as "a bonkers work of immense skill".
"Cooper's work is the stand-out winner. It's hugely ambitious and works on so many different levels. On the one hand, it is very childlike and makes you smile; on the other, it is clearly the work of an experienced artist who knows a great deal about glazing," Dr Scott said.
"There's a sense of wonder about the work, which grows the more you look at it."
Dunedin potters Madeline Child, Jo Howard, Elise O'Neill and Liz Rowe and Waitati potter Kate Fitzharris were also among the 38 finalists chosen from 237 entries.
Portage merit awards of $3000 were presented to potters Fran Maguire, of Blenheim, and Kate McLean, of Auckland.
Cooper has previously won the 2006 Supreme Norsewear Award and 2009 Premier Portage Award.
