To make it as a fashion model is one thing; to endure in such an intensely competitive field, as Christie Brinkley has done, is quite another. It means having to live in constant fear that your job might be snatched by someone younger, or thinner, or whatever the zeitgeist might be hunting for at any given moment. If Brinkley’s new memoir, “Uptown Girl,” has one lesson to impart to its readers, it’s that no one, not even the beauty icon, rides through life for free.

Brinkley, who grew up in Canoga Park and Malibu, was discovered in 1973 by photographer Errol Sawyer at 19 while waiting for a payphone on a Paris street corner. Things went whoosh! and she signed with legendary agent John Casablancas, then decamped to New York, where she worked for Vogue, Harper’s Bazaar and virtually every other fashion magazine on the newsstand. In 1974, Brinkley booked her first job for Sports Illustrated, a collaboration that endures today. (Last year Brinkley appeared, along with Tyra Banks, Martha Stewart and other celebrities, on an SI cover celebrating 60 years of the swimsuit issue.)

Life was grand for Brinkley. She recalls one lunch in the early 1970s with agent Nina Blanchard at the old Brown Derby in Hollywood, when she booked her first three major TV commercials before coffee was served, just by sitting there. Francesco Scavullo, Patrick Demarchelier and Helmut Newton trained their lenses on her and the rest was history. She bought her first apartment in a prewar building on the Upper West Side soon after.

Brinkley bemoans the present colonization of the fashion space by digital media. “There was a kind of dance between photographer and model,” says Brinkley via Zoom from a hotel suite in midtown Manhattan. “You felt as if it was a joint creation, but that’s been lost. Digital photos can be retouched any which way, so what happens on a shoot becomes an afterthought. And there is also the fact of holding a magazine in your hands without being interrupted by pop-up ads.”

In January 1983, while on location in St. Barts for a photo shoot, she met Billy Joel at a motel dive bar. Both were reeling from their previous relationships; Joel had recently divorced his first wife, Elizabeth Weber. Joel played “The Girl From Ipanema” on the bar piano while Brinkley sang along. Brinkley knew nothing about Joel, let alone that he was a global pop megastar.

Two months later, she knew all too well, as Joel wooed Brinkley in grand rock-star fashion. There were thousands of roses, presidential suites in impossibly picturesque hotels, a white horse as a Christmas gift. On her 30th birthday, Joel chartered a Gulfstream III jet to sweep Brinkley from Long Island to his concert in South Bend, Ind., where a grotesquely large cake was rolled onto the stage and 16,000 fans sang “Happy Birthday” to her. The couple got married on March 23, 1985, in the shadow of the Statue of Liberty.

What happened next was like a Nora Ephron script rewritten by John Cassavetes. In the summer of 1986, the couple and their then-4-year-old daughter, Alexa Ray, were staying in a rented cottage in Montauk while Gate Lodge, Joel’s estate on Long Island’s North Shore, was being renovated. One rainy night, Brinkley woke up in the early morning hours to discover her husband had vanished. Shortly before dawn, he returned home, stumbling out of a cab, drunk and ornery. It was the first in a series of scary scenes for Brinkley, whose feelings for Joel vacillated between veneration, unconditional love and abject fear.

“I loved him and I wanted to make it work,” she says. “Drinking is a disease. And I knew that there had to be some way to help him, and not always get to that point where this person who you love is suddenly a stranger to you.” Given the very public nature of their marriage, Brinkley found herself unable to cultivate support for fear that the tabloids would find out about Joel’s addiction. “I was 100% dedicated to Billy, but I never told anyone about our issues, not even my friends,” she says. “It was very difficult in that way, but we had a child together and I was trying to protect the family.”

Then Joel’s issues began to shade into psychosis. Brinkley in her book describes one ugly scene when Joel, deep in his cups, ate a heap of spaghetti directly from a large pan on the stove, then vehemently kicked everyone out of the house for eating his pasta. “I hesitated to put that scene in the book,” she says. “But at the same time, it demonstrates what I was up against.”

Christie Brinkley has maintained a vigorous career as a model and entrepreneur.

(HarperCollins)

Despite the roiling storms she was navigating in her private life, Brinkley’s public persona was expanding beyond fashion’s gilt frame into the American mainstream. By the early 1980s, she had become synonymous with the massively popular Sports Illustrated swimsuit issue, appearing on the cover three years in a row. Then there was the 1983 music video for Joel’s hit “Uptown Girl,” in which Brinkley, wearing a strapless black and white dress, is the unattainable object of desire for the pop star, who plays against type as a working-class car mechanic.

“Suddenly, I had a theme song,” she says. “That was definitely a gift that Billy gave to me.”

Brinkley hacked it for 11 years with Joel, until one final crescendo of boozy madness and a string of well-publicized affairs prompted her to file divorce papers in 1994. As it turned out, this was a mere prelude for a far more traumatic incident in her life. That same year, a helicopter crash on a mountain in Telluride, Colo., nearly killed Brinkley and her five traveling companions. She married crash survivor Richard Taubman, a real estate developer, in the aftermath. The couple had a son and divorced in 1995.

Despite the vicissitudes of her life, Brinkley has maintained a vigorous career as a model and entrepreneur, enduring far longer than her contemporaries, readjusting her approach to the marketplace, finding the niche that eludes everyone else. “In the years after the copter crash, I have maintained an extraordinary sense of gratitude on steroids,” she says. “We’re all so lucky to make it through each day, especially now.”

In other words, nobody rides for free.