Her work incorporates elements of modernism and European Art Deco, combining historical typography with contemporary design approaches.

[4] After graduating, Fili began her career as a freelance designer on special project books at Alfred A. Knopf from 1975 to 1976.

Her approach extended to the physical surface treatment as well, favoring softer and more durable matte coatings over standard shiny finishes.

[4] In 1989, she opened her studio, Louise Fili Ltd., specializing in the design of restaurant identity, food-related logos, and food packaging.

[3] She sought to "change the accepted formulas of food packaging" by pursuing subtle designs, believing that "one does not have to shout to be noticed.

Speaking of the experience in a later interview, Fili said she wanted to send out a clear message with her studio name: "If you have a problem with my being female, then I don’t want you as a client.”[4] She has designed for many New York City eateries such as Pearl Oyster Bar, Picholine, Artisanal, The Mermaid Inn, and Via Carota, and has created packaging for Sarabeth's jam, Tate's cookies, and Bella Cucina.

[8] Her geometric, often Cubist-like designs show an affinity to European Modernism, particularly the work of Lucian Bernhard, A.M. Cassandre, Jean Carlu, and Italian posters of the 1930s.