The name Kolby is of Scandinavian origin, derived from the Old Norse word "kolr," which means "blacksmith." It is believed to have first emerged as a surname in the Viking era, referring to those who worked as blacksmiths or lived near a blacksmith's forge.

The earliest recorded use of the name Kolby dates back to the 11th century in Norway and Denmark. One of the earliest known individuals with this name was Kolby Eriksson, a Norwegian blacksmith who lived in the late 11th century and was renowned for his exceptional craftsmanship.

In the 12th century, the name Kolby appeared in the Icelandic sagas, particularly in the Njáls saga, where it was mentioned as the name of a character. This suggests that the name had gained popularity and recognition among the Norse people during that time.

As the name spread across Scandinavia, it also found its way into other European regions, such as England and Scotland, where it was adapted to various spellings like Colby and Coleby. One notable figure from this era was Colby of Crowland, an English monk and chronicler who lived in the late 12th century and wrote about the history of the Crowland Abbey.

In the 13th century, the name Kolby was recorded in Iceland, with Kolby Bjarnason being a prominent figure. He was a chieftain and lawspeaker in the Icelandic Commonwealth, known for his wisdom and leadership during a turbulent period in the country's history.

Throughout the Middle Ages and the Renaissance, the name Kolby continued to be used across Scandinavia and other parts of Europe, although its popularity waxed and waned. One notable bearer of the name was Colby Tanner, an English merchant and explorer who traveled to the Americas in the late 16th century and documented his experiences in a travelogue.

In the 19th century, the name Kolby resurfaced in various parts of the world, particularly in the United States, where it was adopted by families of Scandinavian descent. One of the most famous individuals with this name was Kolby Allerton, an American businessman and philanthropist who lived from 1835 to 1912 and was known for his contributions to education and social welfare initiatives.