Drew Clark is hitting back his second pint of Kölsch with practiced ease. The founder of the San Francisco–based apparel brand California Cowboy—purveyor of standout party-prepped shirts—is no stranger to good brews. "I love beer, but I'm also really into rum now. There are a few really good rum bars in the city," he says, proceeding to give a meticulous rundown of the key drinking establishments here that specialize in the sailor's jolly. Perhaps it makes sense, then, that Hunter S. Thompson's Fear & Loathing in Las Vegas is a major inspiration. "I've read that book three times already," he grins.

Originally from Los Angeles, Clark made the move to San Francisco in 2001, and cut his teeth in fashion here at Levi's and Gap. Always at the back of his mind, though, was the dream to start his own label: While at USC's Marshall School of Business, he had already written the business plan for what would become California Cowboy. Finally, after more than 15 years in the industry growing other brands, Clark took the plunge to start his own label last April. He funded his first design, the now signature High Water shirt, in an Indiegogo campaign that hit its target amount on the first day. He opened his first store in Nob Hill in January.

The store sits at Polk and Jackson in what used to be an old Radio Shack; a reminder of this can be found in the bright, wood paneled interior where the metal husks of the original Radio Shack sign have been re-appropriated into a Rad Shack sign that, in a hipster interior design coup, graces one side of the shop. The cashier counter is constructed from wood veneers taken from old bowling alley lanes and handily transforms into an airy wooden bar for in-store parties (which happens now and again). In fact, all the store's display pallets can be rejigged for special events.

With California Cowboy, Clark hopes to enable the wearers of his clothes to engage in the social experience. This sounds like big marketing talk, but his designs—both for the clothes and the shop—seem to rise to the challenge. Everything in the store is intended to spark dialogue, from the life-size tipi hand-painted by Mohawk artist Sosakete (it doubles as a changing room) to the brand's signature High Water shirts—with their hand-painted artist prints, these shirts are primed for day drinking. There are also après ski High Sierra shirts ($148) made of warm, luxurious flannel specially sourced from Japan and Portugal, and tricked out with a nifty hidden glove loop and reinforced bottle holder. Both shirts come with a zippered dry pocket, a slim card-sized bottle-opener, and a stack of conversational one-liners discreetly tucked into the inside pocket, just in case you're feeling a little tongue-tied. None of these extras, though, detract from the cool style of the shirts themselves. They resemble the kind of statement togs that Hunter S. Thompson would have appreciated, with additional extras on hand to anticipate serious partygoers' needs.

But California Cowboy isn't just for the boys: Cowgirls can also shop colorful High Sierra styles, as well as a roll-in-bed-soft collection of graphic-print T-shirts ($34-38) and statement La Sirena kimonos that will look right at home poolside at Indian Springs. Clark plans to expand his women's offering in the very near future with a collection of très chic loungewear inspired by glamorous '40s-era society sun-bathers—imagine the kind of style captured in a Slim Aarons' photograph and you'll get the idea. We'll definitely be keeping an eye on this cowboy.

Here are 7x7's top three must-shops from California Cowboy:

The High Water Shirt in Sunset Red. The one that started it all—California Cowboy's iconic High Water shirt ($135) has a hidden bottle opener, slick beer pocket with its own accompanying Koozie, and a super soft custom blended terry cloth lining that'll dry you off in no time. This striking number, with its hand-painted artist print, will make you stand out in all the right ways—even over drinks at Sam's.

La Sirena Kimono. A must for your next pool party, this retro-inspired kimono ($148) is a super-chic wraparound for you to slip into and sip your poolside caipirinha. It's thigh-grazing length makes sun-bronzed legs look longer, while a discreet zippered dry pocket keeps your valuables safe.

Wagyu Fleece Shawl Collar Hoodie. Those unfamiliar with bamboo as a fabric will be firm converts after slipping into this buttery soft hoodie ($108). Made in California, this his/hers grey marl bamboo blend sweatshirt is the ideal accompaniment for a lazy weekend, with the shawl collar detail adding a sweet design finish.

// California Cowboy, 1841 Polk St. (Nob Hill), californiacowboy.com