Each company’s founding myth is important, but the story matters more if it is bundled up in the sales pitch. Filson makes heavy wool jackets and hearty bags and other assorted outdoor gear from a bygone era (no Gore-Tex or Velcro here). Company founder Clinton C. Filson began in 1897, in Seattle, as an outfitter to prospectors headed to the Klondike for the gold rush. The story is central to what Filson is and the company’s appeal. People — men, almost exclusively — have trusted C.C. Filson’s product for more than 100 years for hunting, fishing, prospecting, logging, and other outdoor pursuits. That’s the appeal, and that’s the brand.

The trick is to grow while remaining authentic. It’s a problem Filson’s newest CEO, Alan Kirk, is keenly aware of. Filson is a private company so it doesn’t disclose sales figures, but its revenues have increased 25% year over year since 2010; its jackets and bags appear in the pages of Esquire and GQ and Vanity Fair; it opened a store in London this year and will open one in Aspen by Thanksgiving and New York City by March of next year. Kirk’s job is to take this company that is suddenly the brand of choice for hip urban woodsmen and keep Filson feeling small, unique, and timeless — all while growing and modernizing. Kirk has already seen one company stumble over this challenge, another historic Seattle outfitter that overexpanded to the point of implosion: his previous employer, Eddie Bauer.

MORE: Brand values: Apple +28%, Google +34%, Samsung +20%

After General Mills (GIS) bought Eddie Bauer in the mid-1970s, the company aggressively expanded into malls and lent its logo and sensibility to the likes of Ford, for the Explorer, as well as to joint ventures in Europe and Japan, a home collection, and seasonal lines of casual and office wear. Sales made it to an all-time high in the late 1990s before they plummeted, and the company went bankrupt, twice, in the 2000s. Today it has returned to selling expedition gear and plays up its rich history as an outfitter of mountaineers (Bauer sponsored the first American summit of Everest). The return to form is a direct rebuke to the previous 30 years of growth. Lend a logo, and a sensibility, to too many things, and the brand becomes meaningless, the core customer alienated, and the business suffers. Kirk’s first moves, when he arrived at Filson seven months ago, were aimed at preventing the sort of dilution that happened at Bauer.

“The first few weeks I was here,” he says, “We worked on absolute brand alignment.” He looked at the photography they used, went back through the various styles the Filson catalog had taken on over the years, and even put the logo through a revision. Kirk says it felt “too squiggly.” He cleaned up the font, got rid of the squiggles, and centralized the look “through one lens … The key, throughout, is consistency,” he says.

Until the last decade, Filson was a very slow-moving company indeed. It introduced its best selling cruiser jacket in 1914. Footwear came in the 1950s, bags in the 1980s, and that was pretty much it, until 2005. Before Kirk, Doug Williams, a former Polo Ralph Lauren executive, was the CEO. This was after a private-equity firm based in Los Angeles named Brentwood Associates bought Filson in 2005. It was an odd coupling, “a little like finding out that John Deere was being taken over by a Cadillac executive,” as  Fortune described it. The company launched a line of women’s wear last year and embarked on a few collaborations, one with Levi’s, and another with a Japanese designer.

MORE: Crazy glitz at the World Luxury Expo

Kirk is ending those collaborations. “The approach we’re taking is: It’s less about design. It’s really about product development.” When I asked him what he meant by this, and brought up the idea form following function, he said, “Yes, yes that’s it exactly,” and began describing plans to build “pyramids around each of these iconic items. Take the briefcase — we’re adding a style with ballistic nylon, and an improved Swiss zipper — Riri, the Porsche of zippers, really — they tumble every tooth so it zips smooth as butter. When when we think of Filson in the outdoor and hunting and fishing world, we see similarities to Hermes. They’re 150 years old, started as a saddle maker, they make products in the same facilities, in just a few colors, with a few patterns. The Birkin bag is still a Birkin bag. And it’s repairable for life. It’s an heirloom.” Filson bags are also repairable for life, all one needs to do is send it back to Filson, and 70% of the company’s product is made in a factory in Seattle; but Filson’s bags are about 1/35 the cost of a Birkin (which range considerably but average about $7,000, compared to a $200 Filson), and there is not a six-year waiting list for one.

The biggest change to Filson under its new CEO is the introduction of “The Seattle Fit,” a slimmer, more urban cut of clothing for the more urban set. The traditional cut is now known as “The Alaska Fit.” Kirk’s greatest concern with all change is the possibility of alienating that loyal customer. “We feel as if we’ve opened the funnel to both without upsetting either,” he says. The names of the two categories are a clever nod to the company’s history, and tellingly favor one group more than the other. After all, in the beginning, real men ventured into the North seeking fortune, while C.C. Filson stayed back in the city and made his own. Now the company he built has figured a way to serve both customers.