After graduating from the Royal Academy of Fine Arts in 1981, Demeulemeester found success almost immediately. A year after her graduation, she won the Gouden Spoel, an annually awarded prize to the year's most promising fashion designer. Ann began working as a freelance designer for a few years, and then proceeded to release her own line in 1985 with husband Patrick Robyn. Her first collection was shown in a Parisian art gallery with a makeshift runway and somber models in 1992. In 1996, she debuted her own menswear line.
In 1994, her silhouette became more elongated and streamlined. With a close attention to detail and use of cutting-edge techniques and materials, Ann Demeulemeester consistently produces pieces that are distinctive and instantly recognizable. She began by drawing influence from gothic, punk, and Japanese styles while still remaining true to her own ideas. Though Demeulemeester works with a very specific aesthetic, she continuously strives to push conventions and produce fresh looks for each season. Her pieces, which at times have been described as "funereal", have subtle hints of emotion and emphasis on sexuality.
"I could do it the easy way, give the same pieces, but if I don't try new things then I'm not pushing myself, and I feel bad. I feel lazy."
Despite being approached by major fashion houses (names of which she refuses to divulge), Ann Demeulemeester emphasizes both design and financial independence, and chooses to remain with her own line. She opened her own shop in Antwerp in 1999. Her collections are now sold in over 30 countries worldwide.
Ann Demeulemeester worked with the artist Jim Dine, and draws much of her inspiration from the androgynous singer, Patti Smith. She worked on a clothing line inspired by Jackson Pollock. In June 2013, 32 BVBA fashion house was split the Demeulemeester and Ackermann labels into two independent companies.
In November 2013, Ann Demeulemeester announced she was leaving her eponymous fashion house. The exit letter also explained that the brand will show its autumn/winter 2014 men's and women's collection together at February's Paris Fashion Week