What fabric was most popular for 1970's leisure suits?

Polyester was the most popular fabric for 1970s leisure suits.

A leisure suit was a relaxed alternative to the formal business suit: usually a matching shirt-style jacket and trousers, often with a wide collar, bold colors, flared legs, and eye-catching patterns. Polyester made the style affordable and easy to mass-produce, helping it spread through American fashion during the decade.

The fabric suited the era’s disco culture particularly well. It could be woven into bright colors and shiny textures, resisted wrinkles, and required less maintenance than many natural fabrics. Those qualities made it practical for dancing and travel, even if the material could feel hot and was not especially breathable.

Leisure suits reached peak popularity in the mid-to-late 1970s, strongly reinforced by disco imagery and films such as Saturday Night Fever, released in 1977. By the early 1980s, the look had largely fallen out of fashion. Today, polyester leisure suits are remembered as one of the clearest symbols of 1970s American style and kitsch, although modern casual suits can still use updated synthetic fabrics.