The name “long johns” almost certainly comes from John L. Sullivan, the famous American bare-knuckle boxing champion who fought in the late 1800s. Sullivan was known for stepping into the ring wearing nothing but his long underwear, and as his celebrity grew, the garment became linked to his name. The story is widely repeated, though the term itself didn’t appear in print until decades after Sullivan’s heyday.
The John L. Sullivan Connection
John L. Sullivan (1858–1918) was one of the most recognizable athletes in America during the 1880s and 1890s. While other fighters of his era wore more traditional ring attire, Sullivan entered bouts in just his long underwear. It was a distinctive look that became part of his public identity, and fans associated the full-length undergarment with him.
The most specific version of the story ties the name to a British clothing manufacturer called John Smedley’s Lea Mills, based in Derbyshire, England. Some historians claim that this company introduced its long thermal underwear to the public in the 19th century and named the product after Sullivan, who was a heavyweight celebrity on both sides of the Atlantic. Whether the name started as a marketing decision or simply emerged from popular slang remains unclear.
The Name Appeared Later Than You’d Expect
Here’s the wrinkle in the Sullivan theory: despite his fame peaking in the 1880s and 1890s, the term “long johns” doesn’t show up in print for another half century. The Oxford English Dictionary traces its earliest written appearance to a 1941 issue of The Sheboygan Press, a Wisconsin newspaper, which casually mentioned hoping not to need “long Johns” because the weather was still warm. A 1943 source references “some odd garments affectionately known as longjohns.” By that point, the term was clearly in common use, but no one was explaining where it came from.
Advertisements for thermal underwear from the 1880s and early 1900s don’t use the term at all. Manufacturers sold “union suits,” “unshrinkable underwear,” or simply “drawers.” The gap between Sullivan’s fame and the word’s first documented appearance is long enough that the OED itself labels the origin as uncertain.
Other Theories
A less common theory connects the name to the general nickname “Long John,” which was applied to tall men named John well before Sullivan’s time. The most famous fictional example is Long John Silver from Robert Louis Stevenson’s 1883 novel Treasure Island, described as very tall and strong. Some have speculated the garment’s name plays on the idea of something long associated with a “John,” though there’s no strong evidence linking Stevenson’s character to underwear.
It’s also possible the name is simpler than any of these theories suggest. “Long” describes the garment’s full-length coverage, and “John” was one of the most common men’s names in English-speaking countries. Slang often works this way, attaching a generic human name to an everyday object (think “john” for a toilet). The Sullivan story is the most colorful and widely cited explanation, but the honest answer is that no one has pinned down the exact moment or reason the name stuck.
From Union Suits to Two-Piece Long Johns
The garment we call long johns today is a two-piece set: a long-sleeved top and ankle-length bottoms. But for most of the 1800s, thermal underwear came as a one-piece “union suit” that buttoned up the front and often featured a rear flap. The union suit was the dominant form of cold-weather undergarment throughout Sullivan’s lifetime.
Over time, the two-piece version gained popularity and eventually overtook the union suit. The split made the garment more practical for bathroom trips and easier to layer in varying temperatures. As two-piece thermals became the standard, “long johns” became the go-to casual name for them, while “union suit” faded into nostalgia. Today, the term covers everything from thin moisture-wicking base layers to heavy wool thermals, all descended from the same basic idea of full-body coverage underneath your clothes.