Two events define 1940s fashion more than any others. The first was the beginning of World War II, in 1939. The second was its end, six years and one day later. American trends in the decade can be distinctly divided into those influenced by the changes brought by war—in particular the rationing of materials and the increase in women’s participation in the workforce—and those inspired by the freedom of post-war peace.
By the end of 1942, materials like wool and nylon had joined sugar and coffee on the growing list of rationed goods. Leather shoes would follow suit the next year, and Americans were strongly urged to donate scrap metal to the war effort. As a result, the silhouettes de rigueur at the beginning of the decade were essentially frozen in time, and fashion entered a no-frills period. (Quite literally ruffles were among a list of details, including extra buttons and pockets, eliminated during times of austerity.)
As a growing number of women entered the workforce to fill posts vacated by men at war, the popularity of pants skyrocketed—in part because factory work required the range of motion afforded by trousers, in part because nylon had been diverted from the manufacturing of stockings to the creation of parachutes. Many women sported tailored suits with squared shoulders and narrow waists, sometimes repurposing the suits that languished in their husbands” closets. And simple styles ruled the day as European fashions ceased to be available stateside.
But the tide shifted following the war—not all at once, but gradually, as Paris resumed its place as the headquarters of couture and Christian Dior’s “New Look” reintroduced more traditionally feminine styles. Utility gave way to softness as square shoulders were rounded and slim skirts became fuller. And the late “40s introduced a newly defined segment of the population, and with it a whole new style icon: the teenager.
Liz Ronk edited this gallery for LIFE.com. Follow her on Twitter @lizabethronk.