André Gillier was a French textile manufacturer, best known as the little-known co-founder of Lacoste fashion. He was born in Troyes, France, in a town that was known for its knitwear production industry. Gillier was a graduate of the École Polytechnique, and in 1908, he became the manager of the family knitwear company Établissements Gillier, which had been founded in 1825. He was known for his progressive salary policies, which included the introduction of the first paid holidays for workers in France, thus earning the nickname "the industrial philanthropist."

Gillier was also a great innovator in the fashion industry. In 1929, he created JIL, the first branded men’s underwear and introduced a brief with both an elastic waistband and a side-opening fly. In 1930, he also patented an adjustable waistband for men’s briefs.

Gillier died at the age of 52 on May 16th, 1935. The Gillier family is still active in French fashion with Thierry Gillier, the founder of the luxury brand Zadig & Voltaire Brand being a notable example.