Lhuillier was born to Michel J. Lhuillier, a Filipino businessman of partial French descent and Amparito Llamas, a Filipino society figure and former model of Spanish-Cebuana descent. The Lhuilliers own a chain of pawnshops currently operating in more than a hundred cities in the Philippines.
At 15, she was an outstanding student in Lausanne, Switzerland and hoped to become successful in the fashion industry. Her parents sent her to the Fashion Institute of Design and Merchandising (FIDM), where she met her future husband, Tom Bugbee. The couple founded their company in 1996 and launched their first bridal collection. The line was well-received by fashion-savvy brides, editors, and celebrities. Her dad gave her $30,000.00 to start with.
The breakthrough came after Monique designed the gowns for her wedding entourage. These captured the fancy of couture circles. Having had a difficult time finding her own gown, Lhuillier, a 23-year-old newlywed at the time, decided to begin sketching her own line of dresses. Her husband figured this was little more than a hobby, one that she would tire of soon enough. "He thought I had the wedding blues and eventually I'd get over it", she told USA WEEKEND Magazine.
In 2005, Monique designed a gown for pop icon Britney Spears for her infamous wedding with ex-husband Kevin Federline and since then designed gowns for Kristen Stewart, Kelly Clarkson, Christine Baumgartner, Sarah Gore, Giuliana DePandi, Allison Munn, Shanna Moakler, and Heidi Montag Also, one of her gowns was worn by Hilary Duff in A Cinderella Story.
Subsequently Lhuillier added evening wear to her line, and several of her efforts showed up on red carpets before awards shows. For the Fall 2007 season she branched off into more typical runway collections.On September 18, 2007, Monique Lhuillier launched her spring collection at New York Fashion Week. She introduced mostly sophisticated and fluid looks. Specifically, the Spring collection included: "ready-to-wear formals and cocktail dresses, a collection characterized by ruffles, bows, and pleats in soft fabric and candy colors of vanilla, mint, pistachio and butterscotch."