Rosy-cheeked and eternally boyish in his shrunken suits, Thom Browne makes an unlikely fashion insurrectionist. But with the entire world gone jeans-'n'-T-shirt casual, he believes formality is the truly radical way to dress. So he imagined his precisely tailored clothes worn by radical guys—skiers, skaters, snowboarders. "It was important to get the clothes in motion," he said as he watched his boys spin through fake snow on a mini-rink to the unlikely strains of Rachmaninoff.

It turned out to be the perfect way to highlight the extreme sports detailing (the inset quilting, the elbow and knee patches, the padded calves). Browne hasn't changed his extraordinary signature proportions—the cropped jacket, the shorts, and the little coat with the high half-belt that evoke old pictures of Prince Charles off to boarding school. But for fall he added much longer coats, because after all, legs can get cold in those cutoffs. He also covered bare flesh with long johns, though he was equally taken by socks and garters, which, as he so rightly observed, isn't a look you see on many young men these days.

Browne's more conventional winter wear included his version of the Puffa vest, in corduroy or cashmere, and a fur jacket with a sportily striped revers. One of his mannequins imperiously sported a beaver stole over his gray cashmere-flannel shorts suit. "Like Russian nobility," Browne mused, though such aristocratic connotations were hardly the focus of this energetic show.