Although its exact inventor is unclear, the t-shirt traces its origins back to the U.S. Navy. According to T-shirt Spotlight, Navy officers were first issued t-shirts as undergarments around the time of the Spanish-American War in 1898.
The U.S. Army soon followed suit, adopting the t-shirt as part of the standard-issue uniform given to new recruits. Outdoor workers such as farmers, dockworkers, miners and construction workers soon began to favor the t-shirt due to its lightweight fabric, which made it easier to work in hot weather conditions. Although it was long considered an undergarment, the t-shirt entered the realm of popular fashion during the 1950s, when Marlon Brando popularized the look in "A Streetcar Named Desire."