Beauvais was born in Haiti, to Maria Claire Beauvais, a nurse, and Axel Jean Pierre, a lawyer.

At age seventeen, Beauvais went to New York to pursue a career as a fashion model, and was signed with Ford Models and Irene Marie Models in Miami. She modeled print ads for Avon, Mary Kay and Clairol. Beauvais also modeled in catalogs for Lerner New York Clothing Line, Neiman Marcus and Nordstrom. She has appeared in Essence and Ebony and had a nude pictorial in the August 2007 issue of Playboy. She also walked the catwalk for Calvin Klein and Isaac Mizrahi. In 2008, Garcelle launched her children's jewelry line called Petit Bijou”. She speaks creole

Beauvais has a son, Oliver, born in 1991, from her marriage to ex-husband Daniel Saunders. Beauvais married Mike Nilon, an agent working for the Creative Artists Agency, on May 12, 2001. Their twin sons, Jax Joseph and Jaid Thomas, were born on October 8, 2007, after a five-year struggle with infertility.

In April 2010, it was reported that Beauvais had discovered a five-year extramarital affair by Nilon. She reportedly outed him by sending his CAA co-workers an email, the contents of which were leaked to the New York Post. Beauvais issued a statement on April 9, 2010, explaining that her "focus at this time is on my kids and healing the pain". Beauvais filed for divorce from Nilon on May 10, 2010, seeking joint custody of their sons.