Christmas lights in the modern, electric sense were first created in the early 1880s, with the first known electrically lit Christmas tree appearing in 1882 in New York City.

Key dates in Christmas lights history

  • In the 17th century, people in Germany began decorating Christmas trees with candles , attaching them with wax or pins, which then spread across Europe over the next two centuries.
  • In 1879, Thomas Edison publicly demonstrated long‑lasting incandescent lamps and early “string” lighting at his Menlo Park laboratory, helping set the stage for decorative electric lights.
  • In 1882, Edward H. Johnson, a close associate of Edison, hand‑wired 80 red, white, and blue electric bulbs onto a tree in his New York parlor, widely considered the first true electric Christmas tree lights.

When did they become common?

  • Around 1890–1903, companies linked to Edison and later General Electric began offering electric Christmas light sets for sale or rental, but extremely high prices meant they were mostly a luxury for wealthy households and public displays.
  • By the 1920s–1930s, mass production and home electrification made electric Christmas lights far more affordable, turning them into a standard part of holiday decorating in the United States.

TL;DR: candles on trees go back to the 1600s, but the first electric Christmas lights were invented and displayed in 1882, and became truly popular only once they were cheaper and homes had electricity.

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