William Chambers is the first milliner to collaborate with the company, which specialises in ladies' occasionwear.
The designer, who creates bespoke hats, headpieces and bridal millinery from his studio above Eleganza Sposa in Bath Street, has designed six pieces for the Capsule Collection.
The headpieces, priced from £100, will be sold in selected stores and online from Monday.
The pieces will be stocked in 10 branches of Coast, including its flagship Scottish store in Glasgow's Buchanan Street.
William, 33, a two-time winner of Accessory Designer of the Year at the Scottish Fashion Awards, said: "This collaboration is fantastic. It's exciting to think hats that I designed are going to be sold nationwide with my name on it.
"Hopefully this will be really successful and the customers will have fun wearing them.
"My business is still very small, so any opportunity that I can take to build upon that is really important."
The milliner, who lives in the South Side, has a number of celebrity fans. They include R&B star Kelis, Irish singer Roisin Murphy, Scissor Sister's Ana Matronic, rocker Joan Jett, Colin Firth's eco campaigning wife Livia, Gadget Show presenter Suzi Perry and Vogue Japan's editor-at-large Anna Dello Russo.
This weekend, he will exhibit for a third time at London Fashion Week at Headonism, a showcase for up-and-coming milliners.
At the same even last year, Mr Chambers received orders from Harrods among other top retailers.
It was then William was approached by a buyer at Coast who commissioned him to create eight one-off couture pieces for Coast's new Oxford Street boutique in London.
After the collection sold out, the buying team decided to extend the collaboration to stores across the country.
Kim Elliott, design director for Coast, which has more than 350 outlets around the globe, said: "We're really excited to have collaborated with William on this collection.
"His contemporary take on headwear breathes new life into our accessory offer."
Up to 100 headpieces in each style have been manufactured in an external factory for Coast.
William, who normally makes everything by hand, was keen to ensure that the quality remained high.
He said: "I like things that are couture-made with a real craft in the product.
"It was great to see that the factory replicated my work like-for-like. I'm really happy with the quality."
A graduate of the Scottish College of Textiles in Galashiels, he studied millinery at Glasgow Metropolitan College before setting up his own brand in 2007.
He believes the influence of the Duchess of Cambridge has sparked a renaissance in millinery and that "she's done it in a stylish, youthful way."