In photographs, Tamara Mellon towers like a pair of $900 studded stiletto gladiator sandals. Snapped for Vanity Fair striding down a London street with girlishly long hair streaming over her stylish collar, or dominating red carpet shots in Stella McCartney or Lanvin, the former shopgirl who founded Jimmy Choo 13 years ago exudes unshakable confidence and outrageous brio. Staring down the lens with an enigmatic smile, generous cleavage, understated jewels, and boundless ambition, she is the apotheosis of her customers—or at least of their dreams.

But on a rainy summer afternoon over cappuccino in a midtown Manhattan trattoria, Mellon, in her early forties, shocks with her delicacy. At 5'6" and 115 pounds, dressed in skinny jeans and a featherweight leather jacket, she is more sparrow than Amazon, despite her ever-present five-inch heels. Her blue eyes are wide and watchful, her slender hands with black-violet lacquered nails never quite at rest. Over the years, the tabloid press has described her as “steely,” “controlled,” “man-hungry,” and “aggressive,” but today Mellon’s vulnerabilities are as clear as her complexion. “I’ve learned a lot in the past few years,” she says, her posh accented voice unexpectedly soft, “but really, when you look back at it all at once, it does seem pretty horrendous.”...