Brinkley had a romantic relationship with Olivier Chandon de Brailles, heir to the Moët-Chandon Champagne fortune. The two met in 1982 at Studio 54 in New York City at a party promoting a calendar in which Brinkley appeared. Chandon died a year later in 1983 in an auto-racing accident.

Brinkley has married four times. Her first three marriages were to artist Jean-François Allaux (1973–1981), musician Billy Joel (1985–1994), and real estate developer Richard Taubman (1994–1995).

Brinkley married her fourth husband, Peter Cook, an architect, in 1996, and filed for divorce in September 2006. The public divorce proceedings, held in summer 2008, were regular tabloid fodder, in part due to Cook's admission that he had committed adultery with eighteen-year-old Diana Bianchi. (Describing the experience as a "nightmare," Brinkley contended that, unlike Cook, she had remained faithful.) Press and public interest increased with Cook's revelations that he had paid $300,000