In the best creative marriages, it’s hard to separate the partners’ contributions. That is the case with Black Fleece, the new Brooks Brothers line from designer T h o m Browne. By shrinking and tightening the proportions of the retailer’s classic styles while adding a minimum of his own fashionable peculiarities, Mr. Browne — working closely with Brooks Brothers chairman Claudio Del Vecchio — has created a decidedly wearable collection, at a price point that is less expensive than the line bearing his name. Mr. Browne, a former designer for Club Monaco who struck out on his own in 2001, is known for his 1960s-era uniform-style suit with narrow lapels, and narrow trousers. In Mr. Browne’s $5,000 permutation, however, the ensemble is extremely tight and short — as if it shrank in the dryer. Pants were finished with thick cuffs, at high-water length.

Since Mr. Del Vecchio purchased Brooks Brothers in 2001 from Marks & Spencer, he has struggled to spruce up and gain attention for the brand, which has long been collectively and mysteriously created. Now, the collaboration with Thom Browne is changing that.

Black Fleece’s men’s collection is centered on the signature gray suit, in all its varieties – solid and herringbone flannels, herringbone and Donegal tweeds ($2,700–$2,900). Red and blue stripes and plaids appear sporadically, on a coat, some cashmere sweaters, and some poplin rep ties ($150), but overall, Black Fleece revels in its monochrome world.

The suit is traditional in many details: The lapel is narrow, though not quite as narrow as Mr. Browne’s eponymous line, with three-button front rolls to the second button, and the two cuff buttons are widely spaced. The double rear vent is a useful continental touch, but a locker loop on the back of coats — as well as on pants, shirts, and shoes — seems like a tic. The coat canvassing is soft and the shoulder is too, without build or roping. The pants are lower on the hip, with a flat front and a button fly. Black Fleece style is for the pant leg to actually reach your shoe, ending in a relatively modest (for Browne) 2 1/4-inch cuff.

The soft construction is a must because, when worn to size, the cut is closer than anything else in the store. Looking at a size 38, which in Black Fleecespeak is labeled a BB 1, you see the inversion of the classic ideal of a suit that hides the body’s flaws. So if you are not as thin and cheerfully ascetic as Mr. Browne himself, slim down or size up. Sizes range from 36 to 46.

The oxford and broadcloth shirts are close-fitting as well — and at only $150, which is far less than Mr. Browne’s $385 main line and even less than many in Brooks Brothers’s highest-end Golden Fleece line.

Black Fleece’s line for women — the designer’s fledgling foray into womenswear — comprises menswear staples such as a classic flannel jacket ($1,900), a navy double-breasted wool jacket ($2,100), a plaid cashmere cardigan ($1,200), a white button-down cotton oxford ($150), and a herringbone tie ($150). But Mr. Browne also ventures into a more feminine world of gray flannel dresses and skirts, and evening wear in silk faille, as well as boiled wool and cashmere, with long lines of buttons. Even with a gray herringbone tweed suit with a matching tie, the effect is not aggressively androgynous. Rather, it’s more boyish, as if Audrey Hepburn were dressing up as Marlene Dietrich.

Black Fleece labels, like Browne’s own, are stamped with year and season, which strikes cautionary notes: It warns consumers to buy now, reminding them how the uniform of the architects of the American Century has been revived in a form as perishable as a newsstand magazine.