The Greenock-based manufacturer has been appointed to make a range of Scottish Favourites-branded sweets like Soor Plooms for Asda in a success the company said had helped secure the jobs of its 140 employees.
Golden Casket and Asda believe consumers could buy more than £1m worth of the new range of own label sweets in the retailer's 58 stores in Scotland annually.
Golden Casket will also supply products under its Buchanan's brand.
The contract should provide a welcome boost to trading amid tough market conditions.
The sales value could increase significantly if Asda decides to stock the new lines in its stores south of the Border. The contract has already led to a marked increase in activity at the company, which has installed a new production line to cope with the workload.
Golden Casket said the launch of the own brand products and its Buchanan's branded confectionery into Asda's Scottish stores has meant a significant increase in evening and weekend shifts.
"It is hoped this will transfer into additional jobs in the future," said the company, which also owns Greenock Morton football club.
Noting that the order is the first the company has won to supply own label products to one of the big four supermarkets, commercial manager Robert Murray said the win could have wider significance for the group.
"It's a big step forward," he said. "Now the biggest retailer in the UK is talking to us about developing a range for them in 2014," he added, referring to Tesco.
Mr Murray said Golden Casket supplies products from its own ranges to Morrisons. It hopes to win business from Sainsbury's.
Golden Casket's success with supermarkets has helped it maintain sales in a very difficult market.
"It's probably the hardest it's been in my 16 years in confectionery," said Mr Murray. "Consumers are becoming ever more price conscious."
Golden Casket's owner, Douglas Rae, has highlighted apparent downsides to the supermarket trade.
In the company's 2011 accounts, filed in July last year, the 82-year-old said the company was delighted with the level of support it got from all the supermarkets.
But, he added: "Our relationship with them has come at a price. Our profit margins have been squeezed by them through their failure to fully acknowledge the increases in the commodity market pricing."
Mr Murray said commodity prices have stabilised "somewhat" but the company still faces inflationary pressures under key cost headings like energy and fuel. It remains hard to recover these additional costs.
"The supermarkets just don't like to accept price increases," said Mr Murray.
He said efforts to cash in on the popularity of Scottish products among members of the diaspora overseas have been paying off. The company has been increasing sales in export markets including Canada and New Zealand.
In the year to December 2011, Golden Casket made a £908,000 pre-tax profit on total sales of £19.2m. Exports totalled £945,000.
A qualified banker, Mr Rae started Golden Casket in 1959. He is chairman of Greenock Morton FC.