Casimir Zeglen, a Polish Catholic priest living in Chicago, is most widely credited with inventing the first practical modern bulletproof vest made of layered silk in the 1890s. Later improvements, especially the use of Kevlar in soft armor, trace to chemist Stephanie Kwolek’s invention of the Kevlar fiber in the 1960s–70s.

Quick Scoop

  • The short answer :
    • Inventor of the first practical silk bulletproof vest: Casimir Zeglen (Kazimierz Ĺťegleń), around 1893–1897.
* Key collaborator and rival: Jan Szczepanik, who developed his own silk-and-metal bulletproof waistcoat in the early 1900s.

* Inventor of Kevlar, the fiber behind most modern soft vests: Stephanie Kwolek at DuPont, mid‑20th century.

Early “bulletproof” ideas

  • As far back as the 1500s, European nobles commissioned armor that was supposed to resist early firearms, but these were essentially very heavy steel breastplates, not vests as understood today.
  • In the late 19th century, American surgeon George E. Goodfellow observed that silk garments sometimes slowed bullets and even created a multi‑layer silk vest, a concept that laid groundwork for later inventors.

Casimir Zeglen’s silk vest

  • After the 1893 assassination of Chicago mayor Carter Harrison Sr., Zeglen set out to create a vest that could stop handgun rounds and eventually demonstrated a woven silk design that could defeat low‑velocity bullets of the era.
  • Zeglen’s vest used multiple plies of tightly woven silk, about 1/8 inch thick, and contemporary reports described successful live‑fire demonstrations where he was shot at while wearing it.

Jan Szczepanik’s version

  • Polish inventor Jan Szczepanik worked with Zeglen but went on to develop his own construction using specially woven silk reinforced with small metal plates to trap and slow bullets.
  • His vests gained attention among European elites and royalty, though disputes over credit led to long‑running tension between Szczepanik and Zeglen.

Kevlar and modern bulletproof vests

  • In the 1960s, chemist Stephanie Kwolek at DuPont discovered a new liquid‑crystalline polymer that could be spun into fibers five times stronger than steel by weight, later branded Kevlar.
  • By the 1970s, Kevlar became the core material in lightweight soft body armor, and thousands of police and military personnel now rely on Kevlar‑based vests that are direct descendants of Kwolek’s work.

TL;DR: If you are asking “who invented the bulletproof vest” in the historical sense, most sources point to Casimir Zeglen for the first practical silk vest, with Jan Szczepanik as a key early innovator and Stephanie Kwolek as the chemist whose Kevlar fiber made modern bulletproof vests possible.

Information gathered from public forums or data available on the internet and portrayed here.