Christie attended a French-American high school, Le Lycée Français de Los Angeles then moved to Paris where she enrolled in art school. After graduating she worked as an illustrator in Paris. On the streets of Paris is where an American photographer spotted her. He convinced her that she had what it takes to be a famous model, she was hesitant to leave her creative job. She gave in and became part of the famous Ford modeling agency. Christie was an instant it on catwalks everywhere.

In 1976, she signed a contract with Cover Girl that began their 20-year partnership. industry. In 1979, she appeared on the cover of the swimsuit edition of Sports Illustrated. The editors liked her so much that they asked for a repeat performance the two following years. Christie has appeared on over 500 magazine covers around the world. She is a bona fide superstar. Her presence on the cover of Life magazine made it their best-selling issue of all-time. In addition, she lent her face to such products as Prell shampoo and Chanel perfume.

Unlike other supermodels, Christie had no aspirations of becoming a movie star. However, she did appear as Chevy Chase's fantasy girl in the blockbuster National Lampoon's Vacation.

Christie's popularity faded in the 80's and her All-American looks ceased to be in great demand. Christie turned her attention elsewhere, she hosted the most profitable infomercial in America for Total Gym. The following year, she launched her own perfume, Believe. She also wrote a best-selling fitness book, and is also a gifted photographer. Her photography has been published in periodicals like Autosprint and American Photographer, as well as participating in a number of major boxing events for Don King, as a ring photographer. She has designed a line of women's eyewear and holds several patents for toys for toddlers. 

When Christie is not busy working, she spends her time supporting causes like nuclear disarmament and the Make-A-Wish Foundation.