For years, customers had pleaded with Nack Vorathiankul and her siblings to open a restaurant to showcase the home-style Thai cooking of matriarch Endoo Tonkphontong, then available to the public only in the prepared carryout packages at their two Arlington grocery stores. Last year, the family gave in to popular demand—and the urging of their landlord—and leased an abandoned Goodwill outlet two doors down from their second location.

But running a couple of markets was not the same as running a restaurant, much less a restaurant that was attempting to do battle on the mile-long stretch of Columbia Pike that was already home to Thai Square and Rincome, two of the best Thai restaurants in the entire area. So Nack did something the Vorathiankuls had never done before: She went outside the family, bringing aboard an architect and a publicist/consultant.

How to distinguish the upstart from the competition? Here’s how: a stylish red-and-black color scheme, an open kitchen, and an ambitious wine program, with every thoughtfully chosen white and red available by the glass. Bangkok 54 is a beaut, and you’d be hard-pressed to find an atmosphere as elegant and dramatic and comfortable without paying two or three times as much.

So the hires were well worth it. Still, the decision that augurs best for the place’s staying power was made in-house: to forgo wholesalers and buy directly from local suppliers. Twice a week, a couple of family members head to the Florida Avenue market and load up the cargo van with meats, vegetables, and herbs. And four times a week, they drive out to the waterfront in Southwest to look for the freshest seafood they can find.

This commitment to sourcing locally explains why the longest, most sustained “wow” on my first visit was not for the dazzling décor, nor for finding a pretty good Côtes du Rhône when all I’d expected was a chilled Singha. It was for my first bite of mussel. I’d plucked the thing from a dish called pad cha, a hodgepodge that also includes scallops, shrimp, and squid in a zippy red chili sauce. Nearly every Thai restaurant turns out a variation of this wok-fired dish, which too often amounts to a tired medley of rubbery, dull, overcooked seafood. But this mussel was extraordinary: meaty and sweet, with the sort of seawatery finish that you hope for from oysters on the half-shell. I dug in, hoping that the mollusk was the rule, not the exception. It was. The jumbo shrimp had pop, the scallops were firm and almost fleshy, and the squid approximated the texture of al dente pasta.

Given the mediocrity of the proteins at most Thai restaurants, the seafood at Bangkok 54 amounts to a revelation. There’s lots to love: long, fat tubes of squid, cross-hatched and deep-fried and tossed in a chili-garlic sauce fringed with fried basil; a whole crispy fish, so plump you’ll wonder if it’s been puffed with air, buried under a hail of ginger and shiitake mushrooms; thick, juicy patties of fried minced shrimp; an addictive little appetizer called Firecracker, with tail-on shrimp that hold your interest even after the first, shattering crunch of wonton skin.

The kitchen doesn’t temper the heat of its dishes—a common concession to Western sensibilities. An innocent-sounding green-papaya salad is blistering; the chicken-galangal soup is liquid heat. And the place has not fallen prey to another common flaw of Thai spicing: the permissiveness that enables a single, rogue flavor such as lemongrass to dominate. Tuck into the wonderful larb, a dish often botched, whose elements are here coordinated into a tight, multi-part harmony. Galangal, coriander, fish sauce, lime—all are given a chance to speak.

Oversweetness marred a handful of dishes over the course of my three visits, particularly a clotted rendition of drunken noodles. Curries are surprisingly thin and ordinary, and I wish I could report that the land-animal dishes are as deftly handled as the seafood. Five Spices Stewed Pork is dry and dull; ditto a chicken-studded fried rice with pineapple and cashew. The roast duck, though, is a keeper, its long, thin strips of meat calling to mind the salty, gamy savor of good jerky. Better still is the crispy pork belly, a dish as labor-intensive as it is delicious. The slab of belly is first boiled, then pulled from the pot and poked repeatedly with a fork. Salt is worked into the holes. The slab is then cut up and fried, poked again, and, yes, fried again. If KFC did bacon, it would taste like this. A salty, surface crackle yields, in the next bite, to fatty lusciousness. The tingling garlic-chili sauce keeps the dish from veering into oleaginous overkill, while the crispy fried basil lends it an ineffable perfume.

Nack worries that the dish doesn’t fit in with the health-conscious needs of the crowds the restaurant is attracting, so she’s toying with replacing the pork belly with roasted duck. She’s also planning to add more vegetarian items, including a couple that will be made with brown rice. Oh, and we should expect a few low-carb options as well.

I suppose it’s asking too much to expect the family members, having already heeded the advice of their customers, their landlord, an architect, and a publicist, to be a little less responsive to others. The restaurant, after all, owes its existence to their willingness to keep an open ear. So allow me to drop a little advice of my own: Please don’t sacrifice your authenticity and your soul—to say nothing of your delectable pork belly—to the trendy wishes of the yuppie-crunchy few.

Bangkok 54, 2919 Columbia Pike, Arlington. (703) 521-4070. —Todd Kliman

Eatery tips? Food pursuits? Send suggestions to hungry@washcp.com. Or call (202) 332-2100, x322.