A uniform became a warning sign
In the original Star Trek series, red was commonly worn by security and engineering crew members, while Captain Kirk and many other central characters wore different colors. When an unfamiliar planet or alien threat appeared, a red-clad officer could be sent into danger beside the leads. If that officer died, the scene showed the threat was real without ending the story for a principal character.
That made the uniform useful visual shorthand: viewers could recognize a vulnerable supporting character before learning much about them. The death also gave the danger a human cost, making the heroes’ next decision feel riskier.
A practical device became a running joke
Writers needed ways to establish peril quickly, but the show’s central cast had to survive to continue its ongoing adventures. An unnamed crew member offered a compromise: the episode could deliver a dramatic loss while preserving its regular characters. The tradeoff was that these deaths could feel more like a signal of danger than the end of a fully developed person’s story.
The pattern was never a literal rule that every red-uniformed officer died, and uniform colors changed in later Star Trek series. But the recurring image stuck. Over time, “redshirt” became a pop-culture term for a minor character sent into danger mainly to demonstrate how dangerous it is—an entire plot function condensed into a costume.
